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GemmologyThe Journal of Volume 35 / No. 5 / 2017

The Gemmological Association of Great Britain

Contents GemmologyThe Journal of Volume 35 / No. 5 / 2017

COLUMNS p.386 373 What’s New Multi-colour-temperature lamp|PL-Inspector|AGTA report on Myanmar|ASEAN Gem & p. 388 Jewelry Review|Atypical culturing in P. maxima|Conflict and Cameroon| origin identification using |Global Diamond Industry 2016|ICGL Klaus Schollenbruch photo Newsletter|Japanese journal online|Raman spectrometer sensitivity| demand trends 2016| Expo DVDs|AGTA ARTICLES 2017 Tucson seminars|Color- Jeff Scovil photo Codex colour referencing system| Feature Articles GemeSquare and MyGem- ewizard apps|Gemewizard 404 Synthetic Grown by W. Zerfass: Historical monitor calibration kit|Fabergé Account, Growth Technology, and Properties online|Reopening of The Lap- By Karl Schmetzer, H. Albert Gilg and Elisabeth Vaupel worth Museum of Geology 378 Practical Gemmology 416 Rethinking Lab Reports for the Geographical mystery Origin of Gems By Jack M. Ogden 380 Gem Notes Red matrix cabochons| Gemmological Briefs Ceruleite from Chile|Yellow danburite from Namalulu, 424 Fake Made from Tridacna gigas Shells | from By Michael S. Krzemnicki and Laurent E. Cartier Ethiopia|Vivid purplish pink from Illinois, USA| 430 Large 12-Rayed Black Star from Colourless forsterite from with Asterism Caused by Inclusions Vietnam|Sapphire from By Thanh Nhan Bui, Pascal Entremont and Jean-Pierre Gauthier Ambatondrazaka, | Colour-change from 436 Tsumeb, Namibia|Stichtite| Excursions Zoned type IaB/IIa diamond| Mogok, Myanmar: November 2016 Synthetic star 444 Conferences AGA Tucson|GIT|Jewelry Industry Summit Cover Photo: High-quality , 450 Letters and emeralds are typically ac- companied by geographical origin reports from gemmologi- 451 Gem-A Notices cal laboratories, as discussed on pp. 416–423 of this issue. Shown in this composite photo are 452 Learning Opportunities matched pairs of Colombian em- eralds, Kashmir sapphires and Burmese rubies (total weights 457 New Media approximately 10, 7 and 4 ct, re- spectively). Courtesy of Joseph Ambalu, Amba Gem Corp., New York, New York, USA. 460 Literature of Interest

The Journal is published by Gem-A in collaboration with SSEF and with the support of AGL and GIT.

ISSN: 1355-4565, http://dx/doi.org/10.15506/JoG.2017.35.5 i The Journal of emmology G THE GEMMOLOGICAL ASSOCIATION OF GREAT BRITAIN Editor-in-Chief Production Editor Marketing Consultant Brendan M. Laurs Mary A. Burland Ya’akov Almor [email protected] [email protected] [email protected] 21 Ely Place Editorial Assistant Editor Emeritus Executive Editor London EC1N 6TD Carol M. Stockton Roger R. Harding Alan D. Hart UK Associate Editors t: +44 (0)20 7404 3334 Ahmadjan Abduriyim, Tokyo, Japan; Raquel Alonso-Perez, Harvard University, Cambridge, f: +44 (0)20 7404 8843 Massachusetts, USA; Edward Boehm, RareSource, Chattanooga, Tennessee, USA; Maggie e: [email protected] Campbell Pedersen, Organic Gems, London; Alan T. Collins, King’s College London; John w: www.gem-a.com L. Emmett, Chemistry, Brush Prairie, Washington, USA; Emmanuel Fritsch, University of Nantes, France; Rui Galopim de Carvalho, Portugal Gemas, Lisbon, Portugal; Lee Registered Charity No. 1109555 A. Groat, University of British Columbia, Vancouver, Canada; Thomas Hainschwang, GGTL A company limited by guarantee and Laboratories, Balzers, Liechtenstein; Henry A. Hänni, GemExpert, Basel, Switzerland; Jeff registered in England No. 1945780 W. Harris, University of Glasgow; Alan D. Hart, Gem-A, London; Ulrich Henn, German Registered office: House, Gemmological Association, Idar-Oberstein; Jaroslav Hyršl, Prague, Czech Republic; Brian 1–4 Argyll Street, London W1F 7LD Jackson, National Museums Scotland, Edinburgh; Stefanos Karampelas, GRS Gemresearch Swisslab, Basel, Switzerland; Lore Kiefert, Gübelin Gem Lab Ltd., Lucerne, Switzerland; Hiroshi Kitawaki, Central Gem Laboratory, Tokyo, Japan; Michael S. Krzemnicki, Swiss Gemmological Institute SSEF, Basel; Shane F. McClure, Gemological Institute of America, Carlsbad, ; Jack M. Ogden, Striptwist Ltd., London; Federico Pezzotta, Natural President History Museum of Milan, Italy; Jeffrey E. Post, Smithsonian Institution, Washington DC, Maggie Campbell Pedersen USA; Andrew H. Rankin, Kingston University, Surrey; George R. Rossman, California Institute of Technology, Pasadena, USA; Karl Schmetzer, Petershausen, ; Dietmar Schwarz, Vice Presidents Federated International GemLab, Bangkok, Thailand; Menahem Sevdermish, Gemewizard David J. Callaghan Ltd., Ramat Gan, Israel; Guanghai Shi, China University of Geosciences, Beijing; James Alan T. Collins E. Shigley, Gemological Institute of America, Carlsbad, California; Christopher P. Smith, Noel W. Deeks American Gemological Laboratories Inc., New York, New York; Evelyne Stern, London; E. Alan Jobbins Elisabeth Strack, Gemmologisches Institut Hamburg, Germany; Tay Thye Sun, Far East Andrew H. Rankin Gemological Laboratory, Singapore; Pornsawat Wathanakul, Gem and Jewelry Institute of Thailand, Bangkok; Chris M. Welbourn, Reading, Berkshire; Bert Willems, Leica Microsystems, Honorary Fellows Wetzlar, Germany; Bear Williams, Stone Group Laboratories LLC, Jefferson City, , USA; Gaetano Cavalieri J.C. (Hanco) Zwaan, National Museum of Natural History ‘Naturalis’, Leiden, The Netherlands. Terrence S. Coldham Emmanuel Fritsch Content Submission The Editor-in-Chief is glad to consider original articles, news items, conference/excursion Honorary Diamond Member reports, announcements and calendar entries on subjects of gemmological interest for Martin Rapaport publication in The Journal of Gemmology. A guide to the various sections and the preparation of manuscripts is given at www.gem-a.com/index.php/news-publications/publications/ Chief Executive Officer journal-of-gemmology/submissions, or contact the Production Editor. Alan D. Hart Subscriptions Gem-A members receive The Journal as part of their membership package, full details Council of which are given at www.gem-a.com/membership. Laboratories, libraries, museums and Justine L. Carmody – Chair similar institutions may become Direct Subscribers to The Journal. Kathryn L. Bonanno Paul F. Greer Advertising Kerry H. Gregory Enquiries about advertising in The Journal should be directed to the Marketing Consultant. J. Alan W. Hodgkinson For more information, see www.gem-a.com/index.php/news-publications/publications/ Nigel B. Israel journal-of-gemmology/advertising. Jack M. Ogden Richard M. Slater Database Coverage Christopher P. Smith The Journal of Gemmology is covered by the following abstracting and indexing services: Australian Research Council academic journal list, British Library Document Supply Branch Chairmen Service, Chemical Abstracts (CA Plus), Copyright Clearance Center’s RightFind Midlands – Georgina E. Kettle application, CrossRef, EBSCO (Academic Search International, Discovery North East – Mark W. Houghton Service and TOC Premier), Gale/Cengage Learning Academic OneFile, GeoRef, South East – Veronica Wetten Mineralogical Abstracts, ProQuest, Scopus and the Thomson Reuters’ Emerging South West – Richard M. Slater Sources Citation Index (in the Web of Science). Copyright and Reprint Permission For full details of copyright and reprint permission contact the Editor-in-Chief. The Journal of Gemmology is published quarterly by Gem-A, The Gemmological Association of Great Britain. Any opinions expressed in The Journal are understood to be the views of the contributors and not necessarily of the publisher.

Printed by DG3 (Europe) Ltd. © 2017 The Gemmological Association of Great Britain Understanding Gems ™ Cert no. TT-COC-002454 ISSN: 1355-4565

ii The Journal of Gemmology, 35(5), 2017 What’s New

INSTRUMENTATION

Multi-Colour-Temperature Lamp PL-Inspector The Gem-A Shop is now carrying a Gemetrix Pty Ltd released its multi-colour-temperature lamp that new PL-Inspector instrument in can be used for diamond grading, observ- May 2016 at the Mediterranean ing colour change, and as an ambient light Gem and Conference in source. The 3,700–3,900 K setting is espe- Spain. It contains a portable UV cially useful for viewing and emerald, light source, weighing only 300 4,200–4,500 K is suitable for ob- g, that provides both short-wave serving most coloured stones and (255 nm) and long-wave (365 5,000–5,500 K is ideal nm) radiation for the observation for diamonds and blue of fluorescence and phosphores- sapphires. The lamp has cence in gems (particularly dia- eight levels of brightness mond). An optional battery pack makes the unit suita- controlled by a touch-sensitive slide. The flex- ble for travel. Visit http://gemetrix.thediamondpages. ible head folds for storage. The unit comes with a com/PLinspector.html; for North American orders, go 100/240 V adaptor and a USB-powered connector. to www.gemconference.com/store and for European To order, email [email protected]. CMS orders visit www.iglcert.gr. CMS

NEWS AND PUBLICATIONS

AGTA Report on Myanmar Gem Sector Southeast Asian Nations In October 2016, the American (ASEAN) focuses on the col- Gem Trade Association led a oured stone trade between visit to Myanmar that included Thailand and Myanmar, e- a delegation of American gem commerce opportunities in industry representatives. In Thailand and ASEAN, the January 2017, AGTA released jewellery manufacturing in- a white paper titled ‘Step by dustry in Vietnam, major Step: Myanmar Gem Sector sources of gems and pre- Emerges from Isolation and cious metals in ASEAN, and U.S. Sanctions’ that gives the more. To download the issue, background and outcome of that visit. The report go to www.git.or.th/2014/thai/info_center/trade_ describes several mines visited and the local supply review/2017/2017_ASEAN_Gem_Review.pdf. CMS chain, along with recommendations for the ethical support of the gem sector of Myanmar. To down- load the report, go to http://agta.org/info/docs/ Atypical Pearl Culturing Experiments in P. maxima burmawhitepaper2016.pdf. CMS In February 2017, GIA’s online Research News sec- tion posted a report titled ‘Atypical “Beading” in the Production of Cultured Pearls from Australian ASEAN Gem & Jewelry Review Pinctada maxima’. It describes experiments us- Issue 1, 2017, of this English-language gem and ing low-quality natural pearls and other materi- jewellery trade publication for the Association of als as beads for producing cultured pearls in

What’s New 373 What’s New

P. maxima. Most of and phosphorescence reactions for untreated and the resulting bead- treated natural and synthetic diamonds. Also in- cultured pearls could cluded is a brief review of diamond type classifica- be readily identified tion, causes of colour, treatments, and synthetics using either real- and their detection. The booklet closes with a short time X-ray imaging or article, ‘Identification of CVD-Grown Diamonds on X-ray computed micro the Greek/EU Market with Standard and Advanced tomography. Download Gem Instruments’, by G. Spyromilios, B. Deljanin, the report at www. M. Åström and J. Chapman, followed by a reading gia.edu/gia-news- list. The booklet is available for US$25.00 plus ship- research/atypical-beading-production-cultured- ping and handling from www.gemconference.com/ pearls-australian-pinctada-maxima. CMS store/books/fluorescence-as-a-tool-for-diamond- origin-identification-a-guide. BML

Conflict Diamonds and Cameroon Global Diamond Industry 2016 Partnership Africa Canada released its report Released in December 2016, the 6th annual re- ‘From Conflict to Illicit: Mapping the Diamond Trade port on the global diamond industry prepared by from Central African Re- the Antwerp World Diamond Centre and Bain & public to Cameroon’ in De- Company is titled ‘The cember 2016. It describes Global Diamond Indus- the failure of the Kimberley try 2016: The Endur- Process to prevent conflict ing Allure of Timeless diamonds from CAR from Gems’. The paper re- reaching the international views recent develop- diamond market via adja- ments in the diamond cent Cameroon. The report industry and then de- includes recommendations scribes rough diamond to the Kimberley Process, production, the cutting the government of Cameroon and the diamond in- and polishing industry, dustry to control the flow of conflict diamonds from retail jewellery sales CAR. Download the report at http://pacweb.org/ and how the ‘millennial images/PUBLICATIONS/from-conflict-to-ilicit-eng- generation’ perceives web.pdf. CMS diamonds and diamond jewellery. It concludes with discussions of the current challenges to the industry and an updated model of supply and de- Fluorescence as a Tool for Diamond Origin mand. Download the report at www.bain.com/ Identification—a Guide Images/bain_diamond_report_2016.pdf. CMS In January 2017, this 19-page booklet was re- leased by Gemetrix Pty Ltd, CGL-GRS Swiss Ca- ICGL Fall 2016 Newsletter nadian Gemlab Inc. and Independent Gemological The International Consortium Laboratory to provide a of Gem-Testing Laboratories’ photographic reference for Fall Newsletter (No. 3, 2016) the luminescence behav- was released in December iour of colourless and col- 2016, and features gems oured diamonds. Numer- with unusual colour changes, ous images show typical similar-appearing fluorescence (to long- and and sapphirine gems, a new short-wave UV radiation) ornamental material from

374 The Journal of Gemmology, 35(5), 2017 What’s New

Pakistan called ‘Sannan Skarn’ and sphene from Instruments’, which de- . Visit http://icglabs.org to download this and scribes a technique us- previous issues. CMS ing the 1082 cm–1 feature of a calcium standard to measure the Journal of the Gemmological Society of Japan sensitivity of Raman spec- Online trometers. Download the All issues of this journal, three page report at http:// published from 1974 (Vol. tinyurl.com/zqlfq9s. CMS 1) through 2016 (Vol. 32), were made available online in January 2017. Most of the World Gold Council’s Gold Demand Trends 2016 content is in Japanese, but This annual report on the articles commonly contain gold industry was released in an English abstract. PDF files February 2017 and includes are freely downloadable for extensive data analysis of all but the most recent issue, changes in demand for the 32(1–4), for which access year 2016 compared with to articles and short notes requires a subscriber previous years. Due to high login. Visit www.jstage.jst.go.jp/browse/gsjapan. gold prices, annual jewellery CMS demand for gold declined to a seven-year low. The re- port can be viewed online at www.gold.org/supply- Raman Spectrometer Sensitivity and-demand/gold-demand-trends/back-issues/ In November 2016, TSI Inc. posted online an gold-demand-trends-full-year-2016, which also has application note titled ‘Simple Method for Sen- links to download the complete report, data spread- sitivity Comparison of Raman Spectroscopic sheets and charts, and infographics. CMS

OTHER RESOURCES

2016 Agate Expo DVDs AGTA 2017 Tucson Seminars Released in Septem- Held from 31 January to 5 ber 2016, this set of February 2017, the Ameri- four DVDs contains can Gem Trade Association extensive information (AGTA) GemFair in Tucson, from the 2016 Agate Arizona, USA, featured nu- Expo held 8–10 July merous educational pres- 2016 in Cedarburg, entations covering a broad Wisconsin, USA. In- range of gem, jewellery and cluded on the DVDs industry topics. Approxi- are all 12 symposium mately 26 of the seminars presentations, 10 ad- are available (as audio syn- ditional speaker pres- chronized with the presenters’ PowerPoint slides) entations, the opening on a flash drive that is available to AGTA non-mem- ceremony, highlights from the 128 show displays, bers for US$50.00. (AGTA members can freely ac- vendor interviews and more. To order the set, visit cess the seminars through AGTA’s eLearning on- https://thegemshop.com/collections/publica- line program.) To view a list of topics/presenters tions-1/products/2016-agate-expo-dvd-complete- and place an order, visit www.agta.org/education/ set-pre-order. CMS seminars.html. CMS

What’s New 375 What’s New

ColorCodex Color Referencing System of gems of interest (e.g. at shows or in suppli- Released in early ers’ offices), enabling them to capture their im- 2017, the Color- ages, analyse and record their colours and save Codex is a set of other information, such as their properties, prices, colour-range cards vendor information and more. The apps can then designed for gem be used to share the gem’s information via email colour description. and social media. Visit www.gemeapps.com for ad- Each card has six ditional information and links to download iOS and textured colour im- Android versions. CMS ages for a specific hue that range from lighter to darker and more saturated, with even numbers (to permit communication of interpolated appearanc- Gemewizard Monitor Colour Calibration Kit es) that correspond to each image. The system is In February 2017, Gemewizard Ltd. released a spe- designed for use with both mounted and unmount- cially designed kit enabling users to calibrate their ed gems. Visit www.color-codex.com. CMS computer monitor to display accurate gem colours. The kit con- GemeSquare and MyGemewizard Apps tains a row of six fac- Released in February 2017 by Gemewizard Ltd., the eted pieces of terbium free GemeSquare and MyGemewizard apps make glass representing all it possible to use a of the hues needed smartphone or tablet for calibrating an LCD/ to communicate gem LED screen: blue, red, magenta, green, and colours. The Geme- yellow. The kit is placed under a standard 6,500 K Square app ena- (D65) fluorescent lamp next to the monitor dis- bles users to select playing the Gemewizard calibration page at www. the gem’s colour gemewizard.com/calibration, and the user ad- from a base pal- justs the monitor settings until the colours most ette of 31 mas- closely resemble those shown by the glass sam- ter hues modified by tone and saturation, and ples. The kit will soon be available for US$10.00, translate it into other colour coordinates such and will be included at no extra charge with sub- as Munsell, CIE L*a*b* and CMYK. The My- scriptions to GemePrice. To order, email sales@ Gemewizard app enables users to save records gemewizard.com. BML

MISCELLANEOUS

Fabergé Online The Virginia Museum of Fine Arts in Richmond, Virginia, USA, possesses one of the world’s out- standing collections of Fabergé works, including five Imperial Easter Eggs and more than 170 ad- ditional pieces, donated in 1947 by Lillian Thom- as Pratt. VMFA now offers the ability to search the collection online, as well as a website dedi- cated to the story of the collection, and an app for iOS and Android smartphones and tablets that was launched in October 2016. Visit https:// vmfa.museum/collections/faberge. CMS

376 The Journal of Gemmology, 35(5), 2017 What’s New

Reopening of The Lapworth Museum of Geology In September 2016, the University of Birmingham opened its extensively redeveloped Lapworth Mu- seum of Geology. The Museum’s exhibits cover 3.5 billion years, including rocks, fossils and dinosaurs. The collection contains approximately 12,000 specimens, many from British mining areas that are now closed, as well as historical displays about famous British mineralogists and collectors. For more information about the Museum and its collections, visit www.birmingham.ac.uk/facilities/ lapworth-museum/index.aspx. CMS

What’s New provides announcements of new instruments/ Fine Rubies, Sapphires and Emeralds technology, publications, online resources and more. Bangkok - Geneva - Hong Kong - New York in What’s New does not imply recommendation or endorse- ment by Gem-A. Entries were prepared by Carol M. Stockton (CMS) or Brendan M. Laurs (BML), unless otherwise noted.

Head Office: Color Ltd. 14/F, Central Building, suite 1408, 1-3 Pedder Street Central Hong Kong SAR Tel:+852-2537-8986 New York Office: + 212-223-2363 Geneva Office: +41-22-8100540

Crown Color is a proud supporter of the Journal of Gemmology

What’s New 377 Practical Gemmology

Moonstone Mystery

Alan Hodgkinson

The three cabochons in Figure a b 1a each show an aspect that may be seen in moonstone: cha- toyancy, asterism and adulares- cence (from left to right). The stones on the left and right are in fact moonstones, easily con- firmed by their spot RI of 1.53 Figure 1: (a) The moonstone on the left (6.14 ct) displays , while the and their biaxial interference moonstone on the right (2.40 ct) shows bluish adularescence. The moonstone figure (e.g. Figure 2). Howev- simulant in the centre (6.08 ct), which proved to consist of heat-treated synthetic er, no such figure was obtain- , exhibits asterism with various numbers of rays depending on the orientations of the light source and the cabochon. (b) Exposure of these cabochons to short- able with a polariscope from wave UV radiation revealed faint pinkish red fluorescence in the two moonstones, the cabochon in the centre. It whereas bright ‘sky’-blue luminescence is shown by the synthetic spinel. Photos by was handed to the author at the A. Hodgkinson. 2016 Scottish Gemmological As- sociation conference by a regu- Cross-polarized light re- The high temperature may lar Norwegian attendee, Stig vealed the ‘tortured’ interior have caused lamellae of alu- Sundin, with the question, “Just of the cabochon as a random minium to partially seg- what exactly is the identity?” pattern (Fig- regate, with the resultant ap- Exposure of the three sam- ure 4), which could be due pearance of an adularescent ples to short-wave UV radiation to strain or the exsolution of moonstone. Such cabochons revealed the faintest pinkish red a second phase. This suggest- were in fact posed as star luminescence in the two moon- ed that this moonstone simu- moonstone simulants, but there stones, but striking ‘sky’-blue lant was originally grown as a was little market for such prod- fluorescence in the other cabo- Verneuil colourless synthetic ucts when moonstones them- chon (Figure 1b). The mystery spinel that was then subjected selves from Sri Lanka cost very sample also exhibited various to heat treatment. The heating combinations of asterism de- caused a segregation or ex- pending on the angle of light solution within the structure Figure 2: A biaxial interference figure and viewing, ranging from four, of this flame-fusion synthetic in the polariscope is useful for confirm- ing the identity of moonstone. Photo by five, six or even as spinel (Eppler, 1943; Saalfeld A. Hodgkinson. the cabochon was manoeu- and Jagodzinski, 1957). Un- vred (e.g. Figure 3). like corundum, since it is dif- Martin Donoghue polished the ficult to grow synthetic spinel base of the cabochon, and this by the Verneuil technique, the enabled a clear single RI read- alumina-to-magnesia ratio was ing of 1.727 on an Eickhorst increased by as much as five refractometer. The test results times of that contained in natu- confirmed synthetic spinel, but ral spinel to facilitate growth of what was the mechanism that a product with minimal inter- formed the stars? nal stress (Nassau, 1980).

378 The Journal of Gemmology, 35(5), 2017 Practical Gemmology

also head of the Technical Gem Cutting School at Idar- Oberstein, and it is therefore understandable that such re- ject material would find its way onto their faceting laps and, in the case of cabochons, the by-product had a moonstone appearance with the bonus of also having asterism. To put this article in some perspective, it should be men- Figure 3: Various numbers of rays are Figure 4: A random birefringence pat- shown by the asterism in the 6.08 ct tern, possibly due to strain or the ex- tioned that one of the two fac- heat-treated synthetic spinel. Photo by solution of a second phase, is seen tories charged with growing A. Hodgkinson. when the 6.08 ct synthetic spinel cab- such synthetic , Wiedes ochon is viewed with cross-polarized Carbidwerk at Freyung, pro- light. Photo by A. Hodgkinson. duced 4,000,000 carats of syn- little during that period in the thetic spinel per month (Anony- late 1940s–50s. mous, 1948). It is little wonder The variable-ray stars in that was funded primarily by the that such moonstone imitations such products may be the re- German Luftwaffe (air force). should now turn up on occa- sult of the exsolved lamellae of Central to the German effort, sion! However, they are straight- an -rich phase within Prof. W. Eppler at the Univer- forward to identify with standard the synthetic spinel host. This sity of Strasbourg experimented gemmological instruments—and created multi-random reflec- with heat/annealing processes a knowledge of their existence. tive mechanisms, and so, as the to increase the wear resistance light source and/or specimen of both synthetic spinel and References is manoeuvred, the light paths synthetic sapphire (Steindorff, Anonymous, 1948. The synthetic within the specimen will reflect. 1947). To test this, he devised stone industry of Germany. The The cabochon cut then acts as a sandblast wear-resistance and Gemmologist, 17(201), 96–97. Eppler W.F., 1943. Über das a convex lens to focus the re- hardness test, based on loss of Härten synthetischer Spinelle. flections in various directions weight of a standard polished Zeitschrift für angewandte Min- to the dome surface, hence the sample. Incredibly, in some cas- eralogie, 4(4), 345–362. random and unpredictable na- es he was able to increase the Nassau K., 1980. Gems Made by ture of the star formations. wear resistance of synthetic spi- Man. Gemological Institute of Readers may wonder why nel to a greater factor than that America, Santa Monica, Califor- valuable crystal-growth re- of synthetic sapphire. The ben- nia, USA, 247. sources would be targeted to- efit of this to Germany was im- Saalfeld H. and Jagodzinski H., 1957. Die Entmischung Al O -über- ward simulating such an inex- mense, as it minimized the need 2 3 sättigter Mg-Al-Spinelle. Zeit- pensive gem as moonstone. for industrial diamond powder. schrift für Kristallographie, 109, During World War II, Germany The point of interest here is 87–109. was nearly starved of the cru- that the experiments involved Steindorff E., 1947. German develop- cial commodity of industrial controlled heating sequences. ments in the production of syn- diamond, essential to keep the Apart from the successes of thetic sapphire and spinel. The wheels of war turning. The fric- such work, there would have Gemmologist, 16(186), 28–29. tion obstacle found in all bear- been experiments that did not ings—especially those deployed yield the desired results for in aircraft—required very hard hardening the heated mater- Alan Hodgkinson FGA DGA is and tough materials to offset ial, and it is fair to assume that a gemmology tutor and lecturer wear and abrasion. This result- such items would be rejected. from Ayrshire, Scotland. Email: ed in much effort and expense By chance, Prof. Eppler was [email protected]

Practical Gemmology 379 Gem Notes

COLOURED STONES

Red Beryl in Matrix, Cut as Cabochons It is always interesting to see innovative uses of but it closed several years ago, making this very raw materials, particularly for high-val- rare beryl variety even rarer. ue gem varieties. During the 2017 Tucson gem At the booth of Robert and Patricia Van Wag- shows, this author saw one such example—for oner (Beija-flor Wholesale, Haiku, Hawaii, USA), red beryl from the of south- there were dozens of calibrated cabochons cut west , USA. The Ruby Violet mine was the from red beryl in matrix (e.g. Figure 1). Various only commercial source of gem-quality red beryl, patterns were displayed by the light-coloured, al- tered matrix against the deep red-to-pink beryl, ranging from random-appearing inter- growths to linear patterns that resulted from the crystallization of the red beryl along thin veinlets in the host rock (see, e.g., Figure 9 of Shigley et al., 2003). The cabochons were cut in various shapes (round, pear and oval), and ranged from 4 mm in diameter to 9 × 7 mm. Although it is common for red beryl to be clarity enhanced, these cabochons reportedly were untreated. Brendan M. Laurs FGA

Reference Shigley J.E., Thompson T.J. and Keith J.D., 2003. Figure 1: These cabochons (8 × 6 mm each) are cut from red Red beryl from Utah: A review and update. beryl interspersed with its associated altered rhyolite matrix. Gems & , 39(4), 302–313, http://dx.doi. Photo by Jeff Scovil. org/10.5741/gems.39.4.302.

Ceruleite from Chile

Ceruleite is a blue hydrous aluminium arse- ly 20 pieces weighing 1.0–2.5 ct. Pantò indicated nate, Cu2Al7(AsO4)4(OH)13 • 12(H2O), that is rarely the rough material came from Mina El Guanaco encountered as a gemstone. Although originally in the Taltal area of the Antofagasta Region, Chile. described in 1900 from Chile, gem-quality ce- He kindly donated a 1.45 ct stone to Gem-A, and ruleite was first documented from Bolivia by it was examined by authors CW and BW. Schmetzer et al. (1978). Subsequently, gem-quality The gem was cut in a modified octagonal shape material from Chile was mentioned by Schmetzer and measured 7.15 × 6.90 × 5.02 mm (Figure 2). It et al. (1983). Like , ceruleite is typically was opaque and showed an overall intense blue polished as cabochons. At the 2016 Tucson gem colour (World of Color 5B 7/8), with some dark shows, we encountered ceruleite from Chile that brown, white and green areas corresponding to was faceted and contained various impurities. The impurities. The RIs could not be obtained, proba- stones were offered by Mauro Pantò (The Beauty bly due to the stone’s poor polish. The hydrostatic in the Rocks, Sassari, Italy), who had approximate- SG was 2.69, which is lower than the value of 2.80

380 The Journal of Gemmology, 35(5), 2017 Gem Notes

Figure 2: This 1.45 ct stone consists of intense blue ceruleite Figure 3: This closer view of the pavilion side of the stone in with dark brown, white and green impurities. Gift of Mauro Figure 2 shows the veined appearance of the staining Pantò; photo by B. Williams. and associated matrix material, as well as the green and white impurities in the ceruleite. Photomicrograph by C. Williams; magnified 50×. typically reported for ceruleite, but is similar to the SG of 2.70 determined by Schmetzer et al. (1978) bilization. Schmetzer at al. (1983) documented on polycrystalline mater-ial. The blue areas of the plastic-impregnated ceruleite, which was easily sample were confirmed as ceruleite using an En- identified because its SG was distinctly lower wave 785 Raman spectrometer, by comparing the (2.58) than that of untreated material, and infra- spectra to the RRUFF database. red spectroscopy showed a diagnostic absorption Microscopic observation of the blue areas re- band at 1725 cm–1, as seen in stabilized turquoise. vealed a polycrystalline texture, while the dark Cara Williams FGA and Bear Williams FGA brown areas showed vein-like patterns (e.g. Fig- ([email protected]) ure 3) that resembled the iron-stained matrix Stone Group Laboratories commonly seen in turquoise and the white ar- Jefferson City, Missouri, USA eas locally contained tiny open vugs. According Brendan M. Laurs FGA to analytical work done by German mineralogist Gunnar Farber, the green inclusions consist of References schlossmacherite, a sulphate of the alu- Schmetzer K., Bank H., Berdesinski W. and Kroužek E., 1978. Ceruleite—A new gemstone. Journal nite group with the formula (H O)Al (SO ) (OH) . 3 3 4 2 6 of Gemmology, 16(2), 86–90, http://dx.doi.org/ The reported hardness of 5–6 on the Mohs 10.15506/JoG.1978.16.2.86. scale makes ceruleite sufficiently durable for cut- Schmetzer K., Lind T. and Bank H., 1983. Stabilized ting and use in jewellery. Like turquoise, how- ceruleite. Journal of Gemmology, 18(8), 734–735, ever, it may be sufficiently porous to require sta- http://dx.doi.org/10.15506/jog.1983.18.8.734.

Yellow Danburite from Namalulu, Tanzania: Gemmological Properties and Chemical Composition

Danburite is a calcium borosilicate [CaB2(SiO4)2] amounts of gem-quality yellow danburite entered that is an uncommon collector’s stone. It typically the market, mined from granitic in the ranges from colourless to light brown or light yel- Morogoro region of central Tanzania (Chadwick low, although less commonly it can exhibit in- and Laurs, 2008). A few years later, another de- tense yellow coloration. In early 2008, significant posit of yellow danburite was discovered near

Gem Notes 381 Gem Notes

dispersive X-ray fluorescence (EDXRF) spectros- copy was performed on one sample each from Tanzania and Myanmar with a Thermo Scientific Quant’X instrument, using a series of seven exci- tation energies from 4 to 50 kV (SSEF silicate rou- tine). Laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) was performed on all samples with a GeoLas 193 nm excimer laser, coupled with a PerkinElmer Elan 6100 DRC mass spectrometer (see Table I footnote for de- tails of the procedure). EDXRF spectroscopy revealed the expected major elements Si and Ca; B could not be meas- ured due to limitations of the technique for detect- ing light elements. In addition, low concentrations of Sr were detected in samples from both Tan- Figure 4: These two vivid yellow danburites (8.72 and 7.86 zania and Myanmar. The trace-element data ob- ct) are from the Namalulu area of north-east Tanzania. tained by LA-ICP-MS are shown in Table I; overall, Courtesy of the Somewhere In The Rainbow Collection; the analysed specimens had similar compositions. photo by Bilal Mahmood, AGL. Rare-earth elements (REE) were present in all the samples, with a general enrichment of light REEs Namalulu village in north-east Tanzania. Accord- (La, Ce, Pr, Nd and Sm), as also found by Huong ing to a Tanzanian supplier of this material to et al. (2016) in danburite samples from Tanzania, gem dealer Werner Radl (Mawingu Gems, Nied- Vietnam and Mexico. Our data for the Namalulu erwörresbach, Germany), mining of the Namalulu danburites were similar to the selected elements deposit began in 2012, and production consisted reported by Chadwick and Laurs (2008). However, of hundreds of kilograms of mainly tumble- and our Tanzanian danburites contained higher con- cabochon-grade material, as well as several kilo- centrations of heavy REEs (including Y) compared grams of facet-grade rough. to the samples from Myanmar. Since 2014, one of the authors (CPS) has ex- Due to the fact that elements with even amined a number of the vivid yellow danbur- atomic numbers are naturally more abundant ites from Namalulu, ranging from less than 1 ct than those with odd atomic numbers (so-called to more than 18 ct (e.g. Figure 4). Their stand- Oddo-Harkins rule), REE data are often plotted in a diagram normalized to a chondrite stand- ard gemmological properties were: RIs—nα = ard (stony meteorite; data from Anders and 1.628–1.629, nβ = 1.631–1.634 and nγ = 1.634– 1.637; birefringence—0.006–0.008; hydrostatic Grevesse, 1989). This diagram for our samples SG—2.97–3.01; and fluorescence—inert to both clearly shows the higher abundance of heavy long- and short-wave UV radiation. These data REEs in danburite from Tanzania compared to for Namalulu danburite are consistent with the the Burmese samples (Figure 5). The so-called material from Morogoro reported by Chadwick europium anomaly, a deficiency or enrichment and Laurs (2008). Microscopic features consisted of Eu relative to the other REEs3+, is a common of small colourless , pinpoint particles, se- feature in and rocks, and is linked to ries of fine etch tubules, open fractures with a the fact that this element can be found in two frosted surface appearance and partially healed valence states: Eu3+ and Eu2+ (Weill and Drake, fissures. (The absorption spectra and colour sta- 1973). The danburites from Tanzania were char- bility of Namalulu danburite are described in the acterized by a distinct negative Eu anomaly, following Gem Note entry.) whereas two of the three Burmese samples We measured the chemical composition of showed no such anomaly. However, the pres- three samples of faceted yellow danburite from ence of an Eu anomaly in one of the Burmese Namalulu, as well as three faceted yellow dan- samples precludes the use of this element for burites from Myanmar for comparison. Energy- separating danburites from these two localities.

382 The Journal of Gemmology, 35(5), 2017 Gem Notes

Table I: Average trace-element concentrations in danburite analysed by LA-ICP-MS.* Origin Tanzania Myanmar Weight 2.10 ct 2.93 ct 3.01 ct 1.50 ct 1.60 ct 1.70 ct Element Be 188 (5) 169 (4) 136 (1) 81.3 (22.3) 29.8 (4.2) 202 (11) Na 11.8 (0.2) 13.5 (0.1) 10.1 (0.4) 164 (56) 24.2 (1.4) 156 (8) Mg 4.56 (0.43) 5.55 (0.58) 4.60 (0.22) 5.38 (0.32) 4.91 (0.18) 4.98 (0.46) Al 178.8 (0.6) 129.3 (0.4) 146.9 (1.0) 89.6 (20.5) 474 (53) 82.9 (1.4) P 29.3 (5.0) 36.8 (3.0) 28.2 (0.7) 39.8 (0.9) 31.3 (5.0) 36.5 (6.2) K <2.0 <1.4 <1.5 1.60 (0.12) <2.5 5.5 (0.9) Sc 0.66 (0.08) 0.78 (0.04) 0.39 (0.12) 0.80 (0.12) 0.68 (0.10) 0.49 (0.03) Ti <18 <6.0 14.8 (1.5) <6.3 <20 <19 Mn 1.35 (0.19) 0.50 (0.08) <0.6 <0.45 1.56 (0.12) <0.8 Fe 25.7 (3.8) 26.5 (2.1) 21.3 (3.0) 31.3 (3.4) 23.1 (3.2) 25.2 (3.9) Ga 5.89 (0.62) 10.07 (0.22) 4.07 (0.38) 2.19 (0.27) 4.60 (0.12) 5.08 (0.70) Ge 7.38 (0.24) 6.75 (0.46) 7.07 (0.17) 2.14 (0.17) 3.42 (0.28) 2.48 (0.31) Sr 343 (2) 203 (1) 181 (2) 612 (38) 226 (20) 1037 (12) Y 19.2 (0.3) 13.04 (0.09) 14.68 (0.23) 1.48 (0.14) 5.99 (0.81) 2.11 (0.03) Sn 2.05 (0.15) 1.63 (0.13) 2.00 (0.14) 1.44 (0.26) 2.33 (0.60) 2.01 (0.09) Ba <0.22 <0.14 <0.20 1.75 (0.32) <0.25 9.89 (0.74) La 192 (3) 333 (1) 99 (2) 84 (6) 157 (26) 234 (5) Ce 297 (4) 475 (1) 203 (3) 95 (8) 229 (19) 266 (4) Nd 68.6 (0.8) 91.0 (0.3) 62.4 (0.6) 24.7 (1.6) 42.7 (1.7) 57.4 (2.3) Eu 0.84 (0.03) 0.61 (0.02) 0.56 (0.03) 0.74 (0.13) 0.26 (0.01) 1.32 (0.03) Gd 7.33 (0.20) 6.00 (0.12) 5.91 (0.14) 1.19 (0.21) 2.47 (0.32) 2.10 (0.07) Dy 3.17 (0.04) 2.16 (0.08) 2.58 (0.09) 0.40 (0.01) 1.00 (0.10) 0.55 (0.07) Er 0.96 (0.09) 0.65 (0.01) 0.83 (0.01) 0.077 (0.002) 0.32 (0.04) 0.10 (0.01) Yb 0.50 (0.09) 0.32 (0.02) 0.52 (0.03) <0.08 0.12 (0.03) <0.14 Lu 0.055 (0.003) 0.035 (0.004) 0.062 (0.007) <0.01 <0.02 <0.02 Pb 8.34 (0.11) 11.04 (0.09) 19.16 (0.46) 6.12 (0.51) 7.26 (0.27) 5.82 (0.06) Th 1.39 (0.08) 0.438 (0.012) 0.54 (0.015) 0.009 (0.004) <0.007 0.024 (0.003) * Three analyses were done on the polished girdle of each sample, using a 60 µm spot size. Values are shown in parts per million by weight, and standard deviations are given in parentheses. The raw data were standardized using NIST 610 glass as an external standard and Si as an internal standard. Before each analysis, a short pre-ablation was performed with the laser to avoid surface contamination effects. The concentration calculation of the transient LA-ICP-MS signals was carried out with SILLS data reduction software (Guillong et al., 2008). The isotopes were carefully selected to ensure there were no interferences, and special care was taken in the data processing to correct for any artefact (spike) or contamination (surface or inclusions). The following elements were analysed but were below the detection limits: Li, V, Cr, Co, Ni, Cu, Zn, Rb, Zr, Nb, Mo, Sb, Hf, Ta, W, Bi and U; not analysed were the REEs Pr, Sm, Tb, Ho and Tm.

Nevertheless, the analysed samples from Myan- do, USA), Bill Barker (Barker & Co., Scottsdale, mar and Tanzania could be effectively distin- Arizona, USA) and Shelly Sergent (Somewhere guished by plotting the concentrations of the In The Rainbow Collection, Scottsdale). Useful elements Gd, Dy and Ge (Figure 6). background information on Tanzanian danburite Acknowledgements: The authors thank Prof. Dr was provided by Bill Barker and by Werner Radl. Christoph A. Heinrich and Dr Markus Wälle from Christopher P. Smith FGA ([email protected]) the Institute of Geochemistry and Petrology at American Gemological Laboratories Inc. the Federal Institute of Technology, ETH Zurich, New York, New York, USA. Switzerland, for the LA-ICP-MS analyses. For the loan of samples, the authors thank Dudley Blau- Dr Michael S. Krzemnicki FGA and Dr Hao Wang wet (Dudley Blauwet Gems, Louisville, Colora- Swiss Gemmological Institute SSEF, Basel, Switzerland

Gem Notes 383 Gem Notes

REE Diagram 3D Scatter Plot 10’00010,000

3.5 Myanmar Tanzania 10001000 3.0

2.5 100 100 2.0

Tanzania 10 10 Dy (ppm) 1.5 Sample/Chondrite 1.0 Myanmar 1.0 1.0 0.5

0 2 0.1 0.1 Y La Ce Nd Eu Gd Dy Er Yb Lu Y La Ce Nd Eu Gd Dy Er Yb Lu 4 Element Ge (pp m) 6 8 6 4 8 2 Figure 5: This chondrite-normalized REE diagram of the dan- 0 Gd (ppm) burite samples analysed by LA-ICP-MS reveals their general enrichment in light REEs (La to Sm). The three specimens from Tanzania show distinctly higher amounts of heavy REEs Figure 6: The analysed danburites from Myanmar and (Gd to Lu) than the Burmese samples. All but two of the sam- Tanzania are clearly distinguished in this three-dimensional ples (from Myanmar) show a negative Eu anomaly. scatterplot of germanium, gadolinium and dysprosium.

References 40, Mineralogical Association of Canada, Québec, Anders E. and Grevesse N., 1989. Abundances of Canada, 328–333. the elements: Meteoritic and solar. Geochimica Huong L.T.T., Otter L.M., Macholdt D.S., Foerster et Cosmochimica Acta, 53, 197–214, https://doi. M.W., Stoll B., Weis U. and Jochum K.P., 2016. org/10.1016/0016-7037(89)90286-x. Discrimination of danburite from different Chadwick K.M. and Laurs B.M., 2008. Gem News deposits by chemical components: A femtosecond International: Yellow danburite from Tanzania. LA-ICP-MS study. 35th International Geological Gems & Gemology, 44(2), 169–171. Congress, Cape Town, , 27 August–4 Guillong M., Meier D.L., Allan M.M., Heinrich C.A. September, www.americangeosciences.org/sites/ and Yardley B.W.D., 2008. Appendix A6: SILLS, a default/files/igc/1423.pdf. MatLab-based program for the reduction of laser Weill D.F. and Drake M.J., 1973. Europium ablation ICP-MS data of homogeneous materials anomaly in : Experimental and inclusions. In P. Sylvester, Ed., Laser Ablation results and semiquantitative model. Science, ICP-MS in the Earth Sciences: Current Practices 180(4090), 1059–1060, https://doi.org/10.1126/ and Outstanding Issues. MAC Short Course Vol. science.180.4090.1059.

Yellow Danburite from Namalulu, Tanzania, and Myanmar: Origin of Colour and Its Stability The origin of the yellow colour in danburite is (see preceding Gem Note for sample descrip- not fully known. However, some researchers tions). However, in the larger and more intensely have speculated that it may be due to didymi- coloured samples, a very faint line at approxi- um, a name referring to a mixture of light REEs mately 584 nm could be seen. Using a Perkin- including praseodymium (Pr) and neodymium Elmer Lambda 950 spectrometer, several weak (Nd), and sometimes cerium (Ce). These and bands were recorded in the visible region at ap- other REEs can replace Ca2+. proximately 525, 567, 577, 584, 732, 744 and 792 When viewed with a desk-model spectroscope, nm, as well as two dominant bands in the UV typically no absorption features were observed for region positioned at approximately 275 and 315 yellow danburites from Tanzania and Myanmar nm (Figure 7).

384 The Journal of Gemmology, 35(5), 2017 Gem Notes

Figure 7: UV-Vis-NIR spectra (5.4 mm UV-Vis Spectra path length) are shown for a rough sample of Namalulu danburite, before 525 2.5 0.32 and after heating. The spectrum before heating shows a general 0.30 577 increase in absorption beginning 567 584 2.0 0.28 just below 600 nm, as well as two

0.26 732 dominant bands in the UV region 744 792 positioned at approximately 275 and 0.24 1.5 315 315 nm. After heating, the yellow 275 0.22 sample became colourless with a Absorbance 550 600 650 700 750 800 corresponding decrease in absorption 1.0 from the visible to the UV region of the spectrum; the bands in the UV Before heating region remained unchanged. A series 0.5 of weak absorption bands positioned

After heating at approximately 525, 567, 577, 584, 732, 744 and 792 nm (see inset) 0 300 400 500 600 700 800 appeared to be unaffected by heating. Wavelength (nm)

Although we assume that lanthanides (REE violet-visible-near infrared (UV-Vis-NIR) absorp- with atomic numbers 57–71) are responsible for tion spectroscopy was performed on the samples the colour of these danburites, we could not find before and after heating. In their unheated state, a direct correlation between the yellow colour the yellow danburites showed a significant rise in saturation and the REE concentration in the stud- general absorption from roughly 550 nm leading ied samples from Tanzania and Myanmar. The into the UV region of the spectrum (again, see Fig- colour intensity may therefore be linked to vari- ure 7). After heating, this absorption was greatly able ratios of the valence states of certain lantha- reduced. The mid-infrared spectra (taken with a nides (e.g. Ce2+, Ce3+, Ce4+), in addition to their Thermo Scientific Nicolet 6700 spectrometer) were concentration. virtually unaffected by heating, although a band To test the colour stability of yellow danburite, at 3588 cm–1 did appear slightly diminished. Ad- one of the authors (CPS) heated one rough sample ditionally, no apparent changes were noted in Ra- each from Tanzania (Figure 8a) and Myanmar to man or photoluminescence spectra (recorded with 500°C for four hours, and both showed a com- a Renishaw InVia spectrometer equipped with a plete loss of colour (e.g. Figure 8b). The samples 514 nm Ar-ion laser) in the samples after heating. were then heated further to 950°C for a period We did not perform experiments specifically of 24 hours, but they remained colourless. Ultra- to restore the yellow colour in the danburite

Figure 8: A rough yellow danburite from Namalulu, Tanzania, (a) was heated to 500°C for four hours, resulting in a complete loss of colour, and the sample remained colourless after further heating to 950°C for 24 hours (b). For another test, one bead of Namalulu danburite was kept as a reference sample, while another bead was exposed to a tensor lamp for eight hours (c, left and right samples, respectively). After three hours, the bead exposed to the lamp darkened and became more brownish. Photos by Bilal Mahmood (a, b) and C. P. Smith (c).

a b c

Gem Notes 385 Gem Notes

samples, but exposure of Burmese danburite to colour had become slightly more saturated, yet X-rays is known to induce a yellow or ‘golden’ distinctly more brownish (Figure 8c). After the full brown colour (Webster, 1953); the stability of the eight hours, its colour did not change further. No induced colour was not reported. experiments were performed in an attempt to re- Gem dealers who have handled danburite from store the original coloration, but according to Radl the two localities in Tanzania (Morogoro and Na- this change in colour is permanent and irreversible malulu) have noted a significant difference in their under normal conditions of display or wear. He colour stability to sunlight. While the Morogoro added that mining for the Namalulu danburite has material appears stable, Namalulu danburite de- stopped in recent years due to lack of commercial velops a darker brownish yellow coloration after interest as a result of the susceptibility to develop exposure to sunlight (Werner Radl and Menahem a brownish coloration. Sevdermish, pers. comm., 2016). To test this, author Christopher P. Smith FGA and CPS exposed a yellow danburite from Namalulu to Dr Michael S. Krzemnicki FGA a tensor lamp (positioned 15 cm from the stone) Reference for eight hours and checked hourly for any chang- Webster R., 1953. Gemstone luminescence. Part V. es in colour. After approximately three hours, its The Gemmologist, 22(266), 161–164.

New Production of Emerald from Ethiopia

Ethiopia has been known as a source of emerald for many years, but recently it produced some high-quality material (see, e.g., Figure 9 and Ren- fro et al., 2017) and some fine stones were dis- played by various dealers during the 2017 Tucson gem shows. One vendor, Mahesh Agarwal (Stone International, Jaipur, India), reportedly obtained approximately 1,000 carats of faceted stones (150–200 pieces) that ranged up to 21.70 ct. The emeralds were cut from selected pieces of a par- cel weighing several kilograms that was mined since September 2016 in the Shakiso region of Figure 9: These emeralds (total weight 23.60 carats) report- southern Ethiopia. In addition, Agarwal has ob- edly were produced recently from Ethiopia and were on display at one of the 2017 Tucson gem shows. Courtesy of Mahesh Agarwal; photo by B. M. Laurs. Figure 10: A miner searches for emeralds in a narrow shaft in the Kenticha area of Ethiopia. Photo by Dr Klaus Schollenbruch, © Gübelin Gem Lab. tained ~300 kg of low-to-medium quality rough material. He indicated that the faceted stones were untreated except for light oiling (with min- eral oil), as is typically done for coloured stones after they are cut in Jaipur. According to gem dealer Hussain Rezayee (Rare Gems & Minerals, Los Angeles, California, USA), the recent emerald production took place in the Kenticha area, which is located approxi- mately 40 km south of Shakiso. A series of shal- low pits and shafts (up to a few metres deep; e.g. Figure 10) have been dug by about 500 miners in search of emerald. Production from the area

386 The Journal of Gemmology, 35(5), 2017 Gem Notes

vallos et al. (2012) documented the gemmologi- cal and chemical properties of earlier Ethiopian emerald production, reportedly from the Dubu- luk’ area, which is ~70 km south-west of Kenti- cha. Cevallos et al. (2012) mentioned that during a buying trip to Ethiopia in 2011, gem dealer Fa- rooq Hashmi (Intimate Gems, Glen Cove, New York) was told that the Dubuluk’ area has pro- duced emeralds for a few years. More recently, in September 2013, Hussain Rezayee informed one of us (BML) about some additional production of emeralds from the Shakiso region, including some large crystals—although they contained only small areas that were transparent enough for faceting. During the 2017 Tucson gem shows, Amde Zewdalem, an Ethiopian gem dealer living in Jacksonville, Florida, USA, indicated that some large stones likewise have been produced during the most recent mining (i.e. Figure 11). The area hosting emerald deposits in southern Ethiopia appears quite extensive, and it seems likely that additional commercially significant pro- duction will take place there in the future. Figure 11: Amde Zewdalem holds a large emerald crystal that Brendan M. Laurs FGA he indicated was mined recently in Ethiopia. The sample was Elisabeth Strack FGA previously sliced in two places to extract facetable areas, so Gemmologisches Institut Hamburg the original crystal was somewhat longer. Photo by B. M. Laurs. Hamburg, Germany References has averaged 30–40 kg of mine-run emerald per Cevallos P., Simmons W.B. and Falster A.U., 2012. week, and about 5% of it is gem quality. Gem News International: Emerald from Ethiopia. The gemmological and chemical properties of Gems & Gemology, 48(3), 219–221. Renfro N., Nemeth M. and Sun Z., 2017. A new these -hosted emeralds were described by discovery of emeralds from Ethiopia. Gemological Renfro et al. (2017), who reported that they could Institute of America, Carlsbad, California, www.gia. be separated from those of and by edu/gems-gemology/spring-2017-gemnews-new- their trace-element contents (i.e. Cs, Li, Rb, Sc discovery-emeralds-ethiopia, posted 30 January, and Rb, analysed by LA-ICP-MS). In addition, Ce- accessed 15 February.

Vivid Purplish Pink Fluorite from Illinois, USA

The Illinois-Kentucky Fluorspar District in the It was surprising, therefore, to encounter viv- east-central USA was a famous producer of beau- id purplish pink fluorite from Illinois (e.g. Figure tiful specimens of fluorite and associated min- 12) at the 2017 Tucson gem shows. The stones erals from the early 1800s until 1995, when the were offered by Paul Cory (Iteco Inc., Powell, last operating mine was closed (Goldstein, 1997). Ohio, USA), who had 90 gems cut from a single Fluorite from this area shows a wide variety of large piece of rough that was mined some years colours, with the most common being purple, ago near Cave-In-Rock, Hardin Co., Illinois. yellow and colourless (often as zoned crystals); They ranged from 4 mm in diameter up to ~150 blue and green are less common, and pink is rare ct, with ~20 stones weighing >1 ct. Although (Smath, 2010). the largest stone was rather included, the next

Gem Notes 387 Gem Notes

largest (52.85 ct; Figure 12) was relatively clean, with few eye-visible inclusions. Cory plans to have two more larger-size stones cut from the remaining rough material. While pink is an unusual colour for fluorite from this famous mining area, such a vivid pur- plish pink coloration is notable for fluorite from any locality. Cory decided to have the stones cut on occasion of the theme of the 2017 Tucson Gem and Mineral Show ®, which was ‘Mineral Treasures of the Midwest’; Illinois is one of the states in the American Midwest. Brendan M. Laurs FGA

References Goldstein A., 1997. The Illinois-Kentucky Fluorspar District. Mineralogical Record, 28(1), 3-49. Smath R.A., 2010. Selected Areas within the Western Kentucky Fluorspar District and the Illinois Fluorspar District and a Tour of the Ben E. Clement Mineral Museum. Kentucky Society of Professional Geologists Fall Trip, 23 October, Figure 12: This 52.85 ct fluorite from Illinois, USA, is notable www.kspg.org/pdf/2010%20KSPG%20field%20 for its saturated purplish pink colour. It was faceted by Jay guide%20REPLACEMENT%20PAGES.pdf. Medici (Fredericktown, Ohio). Photo by Jeff Scovil.

Colourless Forsterite from Vietnam

Gem-quality colourless fosterite (the Mg-rich end Luc Yen area are quite thick (up to 500 m), and member of the olivine group) was recently found locally contain pargasite, sulphides, chlorite min- in the Luc Yen region in northern Vietnam. Previ- erals and gem-quality spinels of various colours ously, colourless forsterite was described in gem (Chauviré et al., 2015), which are mined from quality only from the Pyaung Gaung (Themelis, both primary and secondary deposits. 2008) and Dattaw (Krzemnicki and Groenen- The colourless forsterite described here was boom, 2008) mining areas of Myanmar, and from found in coarse-grained white marble together Kukh-i-Lal in the south-western Pamir Mountains with , pink spinel, green pargasite of Tajikistan (Kondo, 2008); it is also known from and . Two pieces of transparent forsterite the Embilipitiya region of Sri Lanka (Gamini Zoy- were separated from the rock and faceted into sa, pers. comm., 2016). oval cuts with dimensions of 5.44 × 4.68 × 3.64 The Vietnamese forsterite occurrence was dis- mm (0.54 ct) and 5.17 × 4.61 × 3.27 mm (0.44 ct; covered in July 2016 by a local miner and author Figure 13). They had RIs of 1.638–1.670, a bire- RH at the Cong Troi mine near the village of An fringence of 0.032 and a hydrostatic SG of 3.25. Phu. This region was influenced by the tectonic The identity of both samples was confirmed by movements of South-East Asia during the clos- Raman spectroscopy (with peaks at 964, 917, 856, ing of the Palaeo-Tethys ocean and subsequent 824, 752, 591, 542, 430, 410, 372, 328, 304 and Himalayan orogeny. The area consists mainly of 226 cm–1). Microscopic examination revealed tiny metamorphic rocks, including mica schist, mar- fluid inclusions and two white anisotropic solid ble and granulite gneiss. The marble layers in the inclusions (probably ) in one of the

388 The Journal of Gemmology, 35(5), 2017 Gem Notes

Vis-NIR Spectra

0.8 0.46 ct 0.54 ct 0.7

0.6 668 740 0.5 645 0.4

Absorbance 0.3

0.2 Figure 13: Weighing 0.44 and 0.54 ct, these colourless 0.1 forsterites are from Cong Troi in the Luc Yen region of northern Vietnam. Photo by R. Hanus and J. Štubňa. 0 400 500 600 700 800 900 Wavelength (nm) samples (Figure 14). Both stones were inert to long-wave UV radiation and fluoresced weak vio- Figure 15: UV-Vis-NIR spectra of the two Vietnamese forster- ite samples show absorptions at 645, 668 and 740 nm, but let to short-wave UV. lack the features typically seen in green at 453, 473 The typical green-yellow colour of peridot (a and 493 nm. solid solution between the end members forst- erite [Mg2SiO4] and fayalite [Fe2SiO4]) is caused by Fe2+ in octahedral coordination. The colour- Vietnam that is known to the authors. It is pos- less appearance of the present forsterite gems is sible that such forsterite may have been inadvert- consistent with its Mg-rich end-member compo- ently sold on the local gem market as microcline, sition, which is also indicated by the RI and SG , colourless spinel or . It seems likely values (cf. Deer et al., 1982). UV-Vis-NIR spectro- that more of this colourless forsterite will be mined scopy revealed absorption bands at 645, 668 and in the future. 740 nm (Figure 15). By comparison, the typical Dr Radek Hanus absorption spectrum of green peridot shows three Gemological Laboratory of e-gems.cz, distinct bands due to iron in the blue region of the Prague, Czech Republic spectrum at 453, 473 and 493 nm (O’Donoghue, Dr Ján Štubňa ([email protected]) 2006), which were absent from the colourless Gemological Institute, Constantine the forsterite. This is the first documented occurrence of col- Philosopher University, Nitra, Slovakia ourless forsterite in the Luc Yen area of northern References Chauviré B., Rondeau B., Fritsch E., Ressigeac P. and Figure 14: The 0.44 ct forsterite contains colourless crystals Devidal J.-L., 2015. Blue spinel from the Luc Yen and fluid inclusions. Photomicrograph by R. Hanus and district of Vietnam. Gems & Gemology, 51(1), J. Štubňa; magnified 90×. 2–17, http://dx.doi.org/10.5741/gems.51.1.2. Deer W.A., Howie R.A. and Zussman J., 1982. Orthosilicates. Rock-Forming Minerals, Vol. 1A, 2nd ed. Longman, London, 336 pp. Kondo D.M., 2008. Gem News International: Colorless forsterite from Tajikistan. Gems & Gemology, 44(3), 265–266. Krzemnicki M.S. and Groenenboom P., 2008. Gem News International: Colorless forsterite from Mogok, Myanmar. Gems & Gemology, 44(3), 263– 265. O’Donoghue M., Ed., 2006. Gems, 6th edn. Butter- worth-Heinemann, Oxford, 873 pp. Themelis T., 2008. Gems & Mines of Mogok. Self- published, 352 pp.

Gem Notes 389

Gem Notes

New Sapphires from Ambatondrazaka, Madagascar

Madagascar, an island of many gem treasures, saw in recent months another gem ‘rush’ after the UV-Vis Spectra discovery of a new sapphire deposit at Bemainty, Fe2+-Ti4+ IVCT located about 35 km east of the small town of Am- Fe3+ Fe3+-rich batondrazaka (Perkins and Pardieu, 2017). With Sapphires about 50,000 artisanal miners working the gravels of this alluvial deposit, this new site has so far re- portedly produced an impressive amount of main- Fe3+ ly blue sapphires, including some large stones up Fe3+ Absorbance (a.u.) Absorbance to 30 g of exceptional quality and additionally some orangey pink sapphires. These stones are Absorbance currently arriving in the gem market in significant quantities, and some of them have been heated to Fe3+-poor improve their colour and clarity. Sapphires SSEF recently analysed a number of sapphires 400 500 600 700 Wavelength (nm) reportedly from this new source ranging from 1.3 ct to 34 ct (Figure 16). Most of the stones showed Figure 17: Absorption spectra are shown for the o-ray (i.e. a rather pure moderately strong to strong blue beam oriented perpendicular to the c-axis) of blue sapphires colour, sometimes with a slight greyish to green- from the new Ambatondrazaka deposit. The spectra were re- ish tint. UV-Vis spectroscopy (Figure 17) showed corded with a portable UV-Vis spectrometer developed by SSEF. that they can be separated into two categories, both of metamorphic origin. One group exhibited only small features due to Fe3+ that are reminis- fine particles in zones and bands (Figure 18a), but cent of sapphires from Sri Lanka and Kashmir only occasionally did they have small rutile nee- with slight turbidity. The other group consisted dles. Some of these sapphires also showed patch- of mostly dark, saturated blue stones with rather es and crossed stripes of coarser particles and distinct Fe3+-related absorption features, as also very fine kinked dust lines (Figure 18b), some- seen in Burmese sapphires. how reminiscent of Kashmir sapphires. We also Many of the studied specimens exhibited a observed characteristics found in gem-quality sap- slight to marked milkiness due to sub-microscopic phires from other metamorphic-related deposits in

Figure 16: These blue (~1.3–34 ct) and orangey pink (~30 ct) sapphires are representative of some of the stones that were recently studied by SSEF from a new deposit near Ambatondrazaka in Madagascar. Photo by Julien Xaysongkham, SSEF.

Gem Notes 391 Gem Notes

a b

Figure 18: These sapphires from the Ambatondrazaka area contain fine milky banding due to minute particles (a, magnified 35×), as well as crossed stripes of coarser particles and very fine kinked dust lines (b, magnified 45×). Photomicrographs by M. S. Krzemnicki.

a b

Figure 19: Also seen in the Ambatondrazaka sapphires are: a dense ‘chaotic’ pattern of growth lines with greyish colour effects (a, magnified 30×) and fine etched hollow channels that emanate from a stone’s girdle (b, magnified 50×). Photomicrographs by M. S. Krzemnicki.

Madagascar (e.g. Andranondambo and Ilakaka), highly characteristic inclusions of Kashmir sap- such as distinct and narrow growth zoning. This phires, such as pargasite needles, short-prismatic zoning also can produce a ‘chaotic’ three-dimen- and corroded long-prismatic . sional pattern, occasionally showing brownish or The dark sapphires rich in Fe3+ from this new greyish colour effects when viewed with transmit- source were often quite clean, sometimes with ted light (seen with brightfield illumination, due to zones of short rutile needles associated with slight variations in ; Figure 19a). A irregular platelets. Many of the dark blue sap- few samples also contained hollow channels that phires we examined also showed small milky appeared to be etched (Figure 19b). Other fea- bands and zones, in contrast to Burmese sap- tures consisted of small colourless prismatic zircon phires that typically contain no such features. inclusions surrounded by tension fissures and a Dr Michael S. Krzemnicki FGA black flake (presumably graphite) with small com- ([email protected]) et-like dust trails. Reference Although the visual appearance of some of Perkins R. and Pardieu V., 2016. Gem News Interna- these sapphires may resemble those from Kash- tional: Sapphire rush near Ambatondrazaka, Mad- mir, we did not find in our samples any of the agascar. Gems & Gemology, 52(4), 429–430.

392 The Journal of Gemmology, 35(5), 2017

Gem Notes

Colour-Change Scorodite from Tsumeb, Namibia

Scorodite is a hydrous iron arsenate with the for- appearance of the stone in transmitted light from 3+ mula Fe AsO4 • 2H2O. The mineral was first de- the halogen lamp. scribed by Breithaupt (1818), who named it after The SG was determined with a hydrostatic the Greek word ‘scorodion’, which means ‘garlic’ balance as 3.29. This is consistent with literature because of the smell of the arsenic vapours pro- data for scorodite (3.29–3.31). The refractive indi- duced when heating or grinding the material. The ces of scorodite are reported as nx = 1.738–1.786, of scorodite is the Asser pit in Langen- ny = 1.742–1.796 and nz = 1.765–1.814, with a berg, Saxonia, Germany. Scorodite is a secondary biaxial positive optic character (cf. Henn, 2012). mineral originating from the weathering of arse- However, it was not possible to determine the RIs nopyrite and other arsenic minerals. A significant of the investigated sample with a standard refrac- source of scorodite is the Tsumeb mine in Namib- tometer because of poor surface polish attributed ia. This deposit is well-known to geologists, min- to its low hardness. Therefore, the identity of the eralogists and mineral collectors, and of the 288 stone was confirmed by Raman spectroscopy. Mi- minerals known from there, it is the type locality croscopic observation revealed fissures, partially for 72 of them (www.mindat.org/loc-2428.html). healed fractures and colourless doubly-refractive Mining of the deposit began in 1907, primarily for mineral inclusions. Qualitative chemical analysis Cu-Pb-Zn-Ag-Ge-Cd . In 1996, when the mine by EDXRF spectroscopy revealed the major ele- closed, a final depth of 1,000 m had been reached. ments Fe and As, as well as traces of Al. Facetable scorodite from Tsumeb was de- In general, the absorption spectra of colour- scribed by Gübelin (1976). Scorodite has a Mohs change minerals show two transmission minima hardness of only 3½–4 and is rarely found in around 476–507 and 625–666 nm, as well as a gem quality, so it is typically considered a collec- strong absorption maximum in the 561–578 nm tor’s stone. In addition, scorodite loses all of its region. Stones that are green in daylight usual- water upon heating to 200–220°C (Gübelin, 1976), ly change to red in artificial light, while bluish which could cause unintended colour and/or green and blue ones typically change to reddish stability alterations. Furthermore, the mineral is violet (Schmetzer et al., 1980). An unpolarized soluble in various strong acids and in some weak absorption spectrum of the 1.41 ct scorodite basic solutions (Weiß, 2000). was recorded with a MAGI GemmoSphere spec- The authors investigated a translucent, faceted trometer. The visible-range spectrum (Figure 21) scorodite (6.99–7.07 × 4.36 mm; 1.41 ct), from was characterized by three absorption bands at Tsumeb that attracted attention because of its ~430, 570 and 800 nm caused by Fe3+ (Lehmann, unusual colour behaviour, which has not been 1978); the 430 nm band is not completely visible described previously in a faceted sample. Viewed in Figure 21 because the signal overwhelmed with a daylight-equivalent lamp (6,774 K), the the detector. The 570 nm band is responsible stone appeared dark green (Figure 20a), but it for the colour change; transmission windows on changed to dark greenish blue under a 3,400 K either side of this strong band (located at 480 and halogen lamp (Figure 20b). With an incandescent 688 nm) correlate to the sample’s colour (Figure lamp or candlelight, the colour changed to vio- 20b–d), depending on the spectral composition letish red. This change appeared strongest with of the light source. When measured with the transmitted incandescent light (Figure 20d). For daylight-equivalent lamp as the light source, the comparison, Figure 20c shows the greenish blue transmission window located at 480 nm shifted

Figure 20: This 1.41 ct scorodite dis- plays different colours in (a) artificial a b c d daylight-equivalent light (6,774 K), (b) halogen light (3,400 K), (c) trans- mitted halogen and (d) transmitted incandescent light (the yellowish hue close to the girdle is an artefact of the light source). Photos by T. Stephan.

394 The Journal of Gemmology, 35(5), 2017 Gem Notes

blue to blue-green, while the samples documented Absorption Spectrum by Weiß (2000) changed from intense blue in sun- 3.0 light to grey-blue or grey-yellow in ‘artificial’ light, pale green in ‘neon’ light and bright yellowish green in the light of an ‘energy-saving’ lamp. 2.5 Tom Stephan ([email protected]) and Fabian Schmitz 2.0 German Gemmological Association

Absorbance Idar-Oberstein, Germany

1.5 Michael Wild Werner Wild e.K., Idar-Oberstein

1.0 References 400 500 600 700 Wavelength (nm) Breithaupt J.F.A., 1818. Gattung M. Skorodit. Handbuch der Mineralogie von C. A. S. Hoffmann, Craz und Figure 21: The visible-range absorption spectrum of Gerlach, Freiburg, Germany, 182–185. the investigated scorodite (here, illuminated with an Gebhard G., 1999. Tsumeb II: A Unique Mineral Locality. approximately 3,400 K light source) displays distinct Gebhard-Giesen Verlag, Grossenseifen, Germany, transmission windows at 480 and 688 nm that account 328 pp. for the colour change. Gübelin E., 1976. Skorodit – ein neuer Edelstein aus Tsumeb, SW-Afrika. Zeitschrift der Deutschen Gemmologischen Gesellschaft, 25(1), 33–39. to 500 nm, causing the dark green colour shown Hänni H.A., 1983. Weitere Untersuchungen an einigen in Figure 20a. farbwechselnden Edelsteinen. Zeitschrift der Deut- Usually Cr3+ and V3+ (and less commonly REEs) schen Gemmologischen Gesellschaft, 32(2/3), 99– are described in the literature as the causes of 106. Henn U., 2012. Gemmologische Tabellen zur Bestimmung a colour change in gems (e.g. Schmetzer et al., von Edelsteinen, Synthesen, künstlichen Produkten 1980; Hänni, 1983). The scorodite described here und Imitationen, 3rd edn. German Gemmological revealed no traces of Cr3+ or V3+ in EDXRF analy- Association, Idar-Oberstein, Germany, 40 pp. ses; also no bands associated with these elements Lehmann G., 1978. Farben von Mineralien und ihre were recorded in the absorption spectrum. There- Ursache. Fortschritte der Mineralogie, 56(2), 172– fore, it appears that Fe3+ (and its associated strong 252. absorption band at 570 nm) is the sole cause of Schmetzer K., Bank H. and Gübelin E., 1980. The the colour change in this scorodite. alexandrite effect in minerals: , , corundum, fluorite.Neues Jahrbuch fur Mineralogie, Gebhard (1999) also mentioned colour-change Abhandlungen, 138(2), 147–164. scorodite from Tsumeb, and Weiß (2000) described Weiß S., 2000. Blauer Skorodit von Hemerdon: it from Hemerdon in south-west England. Gebhard ‘Specimen mining’ im Südwesten Englands. Lapis (1999) described the colour change as greenish Mineralien Magazin, 25(10), 34–40.

Stichtite as a Gem Material

Stichtite, Mg6Cr2CO3(OH)16 • 4H 2O, is an attractive ing striking colour combinations of purple and purplish pink to purple mineral of the hydrotal- yellow-green (e.g. Laurs, 2012). Less frequently cite group that is very soft, with a Mohs hardness encountered are nearly monomineralic stichtite of just 1½–2. Nevertheless, because of its attrac- gems (e.g. Koivula et al., 2003). tive colour, this material is sometimes polished At the 2016 Tucson gem shows, rare-stone as a collector’s stone. Such gems commonly are dealer Mauro Pantò had approximately 50 nearly sourced from Tasmania, Australia, and typically monomineralic faceted stichtites (~1.0–2.5 ct) consist of compact aggregates of stichtite that from South Africa. Two regions in South Africa form in association with , produc- are known to produce stichtite, in Limpopo

Gem Notes 395 Gem Notes

and Mpumalanga Provinces (www.mindat.org/ min-3784.html); the particular origin of Pantò’s stones is unknown. He kindly donated to Gem-A a 1.70 ct faceted hexagon (Figure 22), and it was characterized for this report by authors CW and BW. The stone was opaque with a pinkish purple colour and a waxy . A faint RI was record- ed at approximately 1.54 and SG was measured hydrostatically as 2.11; these values are similar to those reported by Koivula et al. (2003). The sample was inert to both long- and short-wave UV radiation. Microscopic observation revealed a polycrystalline oolitic structure with tiny pearl- escent reflections similar to those com- monly seen in . In addition, small black inclusions were distributed throughout the stone. Raman analysis with an Enwave spectrometer (789 nm laser) confirmed its identity as stichtite. Chemical analysis with an Amptek X123-SDD EDXRF spectrometer showed major amounts of Cr and also some Fe (possibly present within the dark inclusions). Raman analysis of areas contain- ing the dark inclusions was inconclusive, but the presence of Fe combined with the stone’s signifi- cant magnetic susceptibility suggested or ; similar-appearing inclusions were identified as chromite in the sample examined by Koivula et al. (2003). While the low hardness of stichtite does not allow for its common use in jewellery, when cut as a cabochon it may be suitable for

Figure 23: This containing a 13 × 18 mm-wide Figure 22: This stichtite (1.70 ct) was faceted from material cabochon of stichtite was submitted to Stone Group Labor- that was mined in South Africa. The low lustre and rounded atories in mid-2016. It also is set with pale , CVD- facet junctions visible at the lower right are consistent with coated colourless quartz and black , in sterling . the low hardness of stichtite. Gift of Mauro Pantò; photo by Photo by B. Williams. C. Williams.

and other items that receive gentle wear. Such a pendant was submitted to Stone Group Labora- tories in mid-2016, in which stichtite was set with various quartz gems (Figure 23). Cara Williams FGA, Bear Williams FGA and Brendan M. Laurs FGA

References Koivula J.I., DeGhionno D., Owens P., Muhlmeister S., Hurwit K.N. and Tannous M., 2003. Lab Notes: Stichtite flowers. Gems & Gemology, 39(3), 221. Laurs B.M., 2012. Gem News International: Stichtite- dominated intergrowths with serpentinite from Tasmania. Gems & Gemology, 48(3), 229–230.

396 The Journal of Gemmology, 35(5), 2017 Gem Notes

DIAMONDS

A Zoned Type IaB/IIa Diamond of Probable ‘Superdeep’ Origin Few zoned-type diamonds have been document- the DiamondView. A dislocation network typical ed, and most are type IIa/IIb (see, e.g., Reinitz of type II diamond was visible near the culet, and Moses, 1993; Hall and Moses, 2000; Breed- while yellow-emitting graining was seen on a ing, 2005; Chadwick, 2008). Sunagawa (2001) background of blue luminescence in the rest of illustrated a positive image of micro-diamonds the stone. The difference in plasticity between on a photographic plate exposed to 253.7 nm the two zones could be seen near their contact (short-wave UV) radiation, and reported that the (Figure 26); the absence of graining in the type black-appearing stones corresponded to type II portion caused it to appear less ‘rigid’ than its IaA diamond (opaque to SWUV), the transpar- counterpart. ent ones to type II (transparent to SWUV) and The infrared spectrum taken in transmission the grey samples to mixed types I and II. How- through the girdle of the stone showed the pres- ever, no additional spectroscopic investigations ence of type IaB diamond with . Photo- were done on those zoned-type diamonds to luminescence spectra taken with 325 and 514 nm confirm their nature. excitations at liquid-nitrogen temperature showed The Laboratoire Français de Gemmologie marked differences between the two zones (Figure (LFG) in Paris recently examined a notable zoned- 27). The type IIa zone contained more N-V and type 7.28 ct round brilliant diamond. It was GR1 defects than the type IaB zone. In addition, the graded K colour and VS2 clarity due to clouds IaB zone contained 536 and 576 nm defects, which that extended through two-thirds of the stone are linked to B-aggregates. The 491 nm centre (Figure 24). The portion that was free of clouds was detected in the same region, and is often ob- was situated near the culet. Observation of the served in plastically deformed diamonds with the diamond between crossed polarizing filters re- 406 and 423 nm centres (also present here; cf. vealed parallel graining in most of the sample Collins, 2001; Nadolinny et al., 2009). (Figure 25), while a ‘tatami’ pattern was seen in This is the first time that a diamond composed the area near the culet. The latter pattern is spe- of a mixture of types I and II has been docu- cific to type II diamonds. The two portions of mented at LFG. However, Dr Ulrika D’Haenens- the sample also differed in luminescence with Johansson of the Gemological Institute of Amer-

Figure 24: The 7.28 ct diamond (see inset) contains clouds that account

for its VS2 clarity; they are restricted to the type IaB zone of the stone. Photomicrograph by A. Delaunay, © Laboratoire Français de Gemmologie.

200 µm

Gem Notes 397 Gem Notes

1 mm 500 µm

Figure 25: A sharp contrast in anomalous birefringence Figure 26: The DiamondView image of the contact between is seen between the main portion of the diamond, which the type IaB and IIa zones of the diamond illustrates how exhibits parallel graining, and the culet area of the stone. the graining seen in the type IaB portion (bottom) seems to Photomicrograph by A. Delaunay, © Laboratoire Français dissolve into the type IIa zone (top). Image by A. Delaunay, de Gemmologie. © Laboratoire Français de Gemmologie. ica’s New York laboratory indicated to these also consistent with correlations in the behav- authors that she has encountered such zoning iour of type IIa and IaB diamonds, for example, two or three times (pers. comm., October 2016), in terms of UV transparency and high-pressure, but since they were client stones, there was no high-temperature treatment (the rare type IaB time for a detailed study. The presence of such diamonds are transparent to SWUV and can be zoning proves that the formation conditions of HPHT treated to improve their colour; Deljanin type IIa and IaB diamonds may be similar, such and Fritsch, 2001). Furthermore, the association that they can occur in a . This is of type IaB diamond with low-nitrogen type IIa

Figure 27: Liquid-nitrogen temperature photoluminescence spectra of the two zones of the diamond with 325 and 514 nm laser excitation show that the type IaB zone contains numerous defects, such as the 406.2 nm, N3 (415 nm), 491 nm, H4 (496.1 nm), 536 nm, 576 nm, 612 nm and a very weak GR1 (741 nm) centre, whereas the type IIa zone contains only very weak emissions of the N3, H4 and H3 (503.3 nm) centres, a trace of the GR1 (741.3 nm) defect, weaker emissions of the 536 and 612 nm centres, and N-V– and N-V0 features (637 and 575 nm, respectively).

Photoluminescence Spectra

325 nm Excitation 514 nm Excitation 637 491.0 Raman Raman N−V− 8000 415.3 24000 N3 496.1 7000 H4 20000 536.2 575 6000 N−V0 528.8 16000 5000 505.3 741.3 4000 12000 612.5 Counts Counts GR1 422.8 Type IaB zone 3000 406.2 8000 536 Type IIa zone 2000 503.3 H3 Type IIa zone 4000 Type IaB zone 1000 576 0 0 340 360 380 400 420 440 460 480 500 520 540 550 600 650 700 750 800 850 900 Wavelength (nm) Wavelength (nm)

398 The Journal of Gemmology, 35(5), 2017 Gem Notes

diamond showing a high level of nitrogen ag- Chadwick K.M., 2008. Lab Notes: Fancy dark brown- gregation, formed under high pressure and tem- yellow zoned type IIa/IIb diamond. Gems & perature conditions, is consistent with ‘super- Gemology, 44(4), 364–365. deep’ diamonds—those derived from the base Collins A.T., 2001. The colour of diamond and how it may be changed. Journal of Gemmology, of the lithosphere down to about 600 km (see, 27(6), 341–359, http://dx.doi.org/10.15506/JoG. e.g., Burnham et al., 2016)—rather than about 2001.27.6.341. 150 km, where most diamonds form. Deljanin B. and Fritsch E., 2001. Another diamond Aurélien Delaunay ([email protected]) type is susceptible to HPHT: Rare type IaB Laboratoire Français de Gemmologie, Paris, France diamonds are targeted. Professional Jeweller, October, 26–29. Dr Emmanuel Fritsch FGA Hall M. and Moses T., 2000. Gem Trade Lab Notes: Institut des Matériaux Jean Rouxel Diamond, blue, zoned. Gems & Gemology, 36(2), CNRS, Team 6502, University of Nantes, France 156–157. Nadolinny V.A., Yurjeva O.P. and Pokhilenko N.P., 2009. EPR and luminescence data on the nitrogen References aggregation in diamonds from Snap Lake dyke Breeding C.M., 2005. Lab Notes: Light , system. Lithos, 112, 865–869, http://dx.doi.org/ with type IIb and IIa zones. Gems & Gemology, 10.1016/j.lithos.2009.05.045. 41(2), 167–168. Reinitz I. and Moses T., 1993. Gem Trade Lab Notes: Burnham A.D., Bulanova G.P., Smith C.B., Whitehead Light violet-gray diamond. Gems & Gemology, S.C., Kohn S.C., Gobbo L. and Walter M.J., 2016. 29(3), 199. Diamonds from the Machado River alluvial deposit, Sunagawa I., 2001. A discussion on the origin of Rondônia, Brazil, derived from both lithospheric irregular shapes of type II diamonds. Journal and sublithospheric mantle. Lithos, 265, 199–213, of Gemmology, 27(7), 417–425, http://dx.doi. http://dx.doi.org/10.1016/j.lithos.2016.05.022. org/10.15506/JoG.2001.27.7.417.

SYNTHETICS

Synthetic Star Ruby with an Unusual Production History The process for manufacturing synthetic asteriat- nounced zoning but which differed from the ed ruby and sapphire was invented by research- more common scenario just described. The sam- ers J. N. Burdick and J. W. Glenn in the late ple had been kept in the teaching and refer- 1940s and was patented by the Linde Air Prod- ence collection of author LR for several decades, ucts Company (Schmetzer et al., 2015). Grown but the original producer is unknown. The cab- by the Verneuil technique, early samples fre- ochon, weighing 4.20 ct, was examined with quently showed—after annealing to form rutile fibre-optic illumination and in immersion in precipitates—an inhomogeneous distribution of transmitted light using a gemmological micro- colour and inclusions between the cores and the scope (up to 100× magnification), and at higher rims of the boules. In such samples, this zoning magnification (up to 1,000×) with a Leitz Or- of colour and rutile precipitates often caused the tholux II Pol-BK polarizing microscope. resulting six-rayed stars on their surface to ap- In reflected light, the sample showed a typical pear broken or partially absent in areas where six-rayed star on its surface and displayed a rather the zoning had depleted the cabochon of tita- milky appearance (Figure 28a). Conversely, the nium (Schmetzer et al., 2015). base of the cabochon consisted entirely of transpar- In examining historical samples of synthetic ent synthetic ruby material, without any milkiness asteriated corundum from various collections, (Figure 28b). Between crossed polarizers and in a one of the authors (KS) recently observed a view parallel to the optic axis (i.e. approximately synthetic star ruby that likewise displayed pro- perpendicular to the base of the cabochon), the

Gem Notes 399 Gem Notes

a b

Figure 28: This 4.20 ct synthetic star ruby is shown in two views: (a) toward the milky, translucent dome of the cabochon, and (b) toward the transparent base of the cabochon. The photo of the dome side is focused slightly above the cabochon’s surface, where the star appears sharpest. Fibre-optic illumination; photos by K. Schmetzer. sample showed a series of parallel striations, re- of the base, revealed curved growth striations ferred to as ‘Plato lines’ in gemmological literature that were oblique to the boundary between the (Figure 29). These striations represent glide planes core and rim of the sample (Figure 30). Within - parallel to the second-order hexagonal prism {1120} the rim, but close to the core of the sample, an and are caused by internal stress generated during almost opaque zone with a high concentration the Verneuil process used for crystal growth. of inclusions, mostly in the form of non-trans- In views nearly parallel to the base of the cab- parent, irregularly shaped particles, was present. ochon, it became apparent that the sample con- A further inclusion feature was a that sisted of two principal parts. The outer portion, extended through the cabochon from the base comprising the dome of the cabochon, showed to the dome. a curved structure of sequential shell-like lay- At higher magnification, three sets of needle- ers. These layers generally followed the exter- like precipitates, forming angles of 60° with one nal form of the dome. In contrast, the central another, were visible in the milky rim (Figure 31). part of the cabochon, including the central part The transparent red core was free of such needles.

Figure 29: Between crossed polarizers, three series of parallel striations are visible in a view parallel to the optic axis of the synthetic star ruby. These striations (Plato lines) represent glide planes parallel to the second-order hexagonal prism. Immersion, field of view 4.6 × 3.4 mm; photomicrograph by K. Schmetzer.

400 The Journal of Gemmology, 35(5), 2017 Gem Notes

Figure 30: In these views nearly parallel to the base of the synthetic ruby cabochon, the sample can be seen to consist of two principal parts: a Verneuil-grown core of transparent synthetic ruby without rutile needles, and a Verneuil-grown somewhat milky rim of synthetic ruby containing rutile precipitates. In the rim, shell-like layers approximately follow the external form of the cabochon; in the core, curved Verneuil striations are oriented obliquely to the core-rim boundary. Within the rim, close to the core, an almost opaque zone with a high concentration of inclusions is seen. In addition, a fracture runs vertically through the stone. Immersion, field of view 8.8 × 6.5 mm (left) and 7.8 × 5.9 mm (right); photomicrographs by K. Schmetzer.

The foregoing observations thus established Oriented seeds are necessary for control of that production of this star sample began from a crystal orientation in the Verneuil process, a par- cabochon of transparent Verneuil-grown ruby. That ticularly important factor when the aim is to pro- cabochon was used as a seed for the growth of a duce star material. This technique was invented Verneuil crystal with high Ti concentration, there- independently in Germany and in the United by enabling formation of rutile precipitates upon States in the 1940s (see again, Schmetzer et al., subsequent annealing. Such an approach is analo- 2015). Without such oriented seeds, the orienta- gous to the classical method for manufacturing star tion of the Verneuil-grown synthetic ruby and corundum, but normally small seeds of oriented sapphire crystals is unpredictable, and conse- natural or synthetic ruby or sapphire are used. The quently, each crystal must be individually exam- small seeds are then removed when asteriated cab- ined to find the optic axis for cutting cabochons ochons were cut for jewellery purposes. with well-centred stars. In the present case, use of a synthetic ruby cabochon for the seed also explained the high Figure 31: Three sets of rutile needles in the synthetic star ruby cabochon are responsible for the reflection and scattering of concentration of non-transparent, irregularly light that generates asterism. Reflected light, oil immersion, field shaped inclusions near the boundary between of view 92 × 69 µm; photomicrograph by H.-J. Bernhardt. the core and rim portions. These inclusions were trapped at the dome of the seed cabochon at the beginning of crystal growth, before more stable growth conditions were achieved. Dr Karl Schmetzer ([email protected]) Petershausen, Germany Prof. Leopold Rössler Vienna,

Reference Schmetzer K., Steinbach M.P., Gilg H.A. and Blake A.R., 2015. Dual-color double stars in ruby, sapphire, and quartz: Cause and historical account. Gems & Gemology, 51(2), 112–143, http://dx.doi. org/10.5741/gems.51.2.112.

Gem Notes 401 European Gemmological Symposium 2017 to mark the 75 year Anniversary of the Swiss Gemmological Society SGG/SGS

Friday 30th June and Saturday 1st July 2017

Grand Hotel Zermatterhof, Zermatt, Switzerland

During the two days of the Conference, there will be an impressive lineup of internationally renowned speakers presenting a broad spectrum of gemmologically relevant topics about diamonds, coloured , pearls, and jewellery.

Keynote speaker: Martin Rapaport (USA)

Honory guest: Adolf Ogi, former Federal Councillor of Switzerland

Further speakers include: Alan Hart (Gem-A, UK), Vincent Pardieu (Thailand), Bruce Bridges (), Jeff Scovil (USA), Ulrich Henn (DSEF, Germany), Hanco Zwaan (Museum Naturalis, NL), Wuyi Wang (GIA, USA), Andrey Katrusha (New Diamond Technology, ), Raquel Alonso-Perez (Harvard Museum, USA), Bernhard Berger (Cartier Tradition, CH), Guillaume Chautru (Piaget, CH), Alan Hodgkinson (Scotland), Joseph Taylor (PT Cendana Indopearls, Indonesia). and from the Society: Michael Hügi, Thomas Hainschwang, Henry A. Hänni, Helen Molesworth, Willy Bieri, Michael S. Krzemnicki, Daniel Nyfeler, Klemens Link, Laurent Cartier, Franck Notari.

For further information and registration: www.gemmologie.ch

Feature Article

Synthetic Emeralds Grown by W. Zerfass: Historical Account, Growth Technology and Properties

Karl Schmetzer, H. Albert Gilg and Elisabeth Vaupel

Rough and faceted synthetic emeralds were produced by W. Zerfass in Idar- Oberstein, Germany, between 1963 and 1973. The synthesis process was developed in cooperation with the chemist G. H. Jaeger; experiments started in 1952 and led to samples of facetable size in the early 1960s. Microscopic examination and chemical analysis of rough and cut Zerfass samples indi- cate that crystal growth took place on oriented seed plates cut from synthetic emerald crystals within a molybdate melt. Only was added to the nutrient as a colour-causing trace element. Although the growth method was similar to that developed by H. Espig in the 1930s and applied by the IG Farben company, the process used by Zerfass and Jaeger was developed independently and, contrary to certain statements in the gemmological liter- ature, did not involve anyone who had formerly worked with Espig at the IG Farben plant in Bitterfeld, Germany.

The Journal of Gemmology, 35(5), 2017, pp. 404–414, http://dx.doi.org/10.15506/JoG.2017.35.5.404 © 2017 The Gemmological Association of Great Britain

Introduction on the form and distribution of inclusions, that In 1963, a new synthetic emerald grown by W. the synthetic emeralds were grown through a Zerfass in Idar-Oberstein, Germany, was intro- flux-melt process. In contrast, Gübelin assumed a duced to the market. The production technique, hydrothermal origin, deduced from the presence however, was not disclosed. Several descriptions of inclusions formed by tapered conical channels of the material followed shortly after its introduc- with small crystals attached to their wider ends tion (Schlossmacher, 1963; Eppler, 1964; Gübelin, (commonly called ‘nail-head spicules’). Further 1964a,b). Schlossmacher mentioned that the sam- work by E. M. Flanigen and colleagues at the ples, especially in small sizes, were of high qual- Linde division of Union Carbide Corp. (Flanigen ity, resembling in colour (e.g. et al., 1965, 1967) then considered the available Figure 1). No information was offered regarding evidence, but without the benefit of directly ex- the chemical compounds used for crystal growth, amining samples produced by Zerfass. Comparing and he did not speculate as to the production different types of hydrothermal and flux-grown technology. The latter topic was instead taken up synthetic emeralds, they noted that nail-head spic- by subsequent writers. Eppler concluded, based ules could be formed by both growth methods,

404 The Journal of Gemmology, 35(5), 2017 Feature Article

Figure 1: Shown here are faceted and rough synthetic emeralds grown by W. Zerfass in Idar-Oberstein, Germany, in the 1960s. The faceted samples weigh 0.24–1.02 ct, and the crystals are 0.23 and 0.40 g; the faceted sample on the upper left measures 6.4 × 6.4 mm and weighs 1.02 ct. Photo by K. Schmetzer.

provided the seed plates used had been cut at an of the properties of Igmeralds (Schmetzer et al., incline to the beryl crystal faces. Therefore, taking 2016a), the present authors also examined syn- into account the relatively low SG and RI values thetic emeralds grown by R. Nacken in the 1920s (as reported by previous researchers), they con- (Schmetzer et al., 2016b) and by Zerfass. These cluded that the Zerfass synthetic emeralds had investigations were prompted by reports that the been created through flux-melt growth. However, Nacken and Zerfass material had been grown in the absence of any published chemical data, the by processes similar to those used for Igmeralds production method remained a matter of discus- and/or that various people or companies involved sion (O’Donoghue, 1980). might have collaborated. Thus, efforts were under- In addition to the foregoing focus on the taken to delve into historical facts and to correlate production technique, and despite the relative the properties of faceted and rough samples with rarity of the material in the marketplace (see knowledge about the growth techniques applied. Crowningshield, 1970), details about the indi- viduals involved were also of continuing in- Collaboration by W. Zerfass and terest. In the early papers describing the new synthetic emerald, an unnamed ‘inventor’ or Dr G. H. Jaeger ‘co-worker’ was mentioned along with Zerfass Walter Zerfass1 (Figure 2) was a gem cutter in (Schlossmacher, 1963; Eppler, 1964). Later, Nas- Idar-Oberstein leading a small, independently sau (1976a,b) offered the following based upon owned company. His son, chemist Dr Torsten Zer- an unpublished interview with Zerfass con- ducted by R. Crowningshield: “The Zerfass emer- alds were grown for a time in small quantities 1 W. Zerfass (1911–1995) was trained as an agate cutter and by one of Espig’s I.G.-Farben co-workers after worked in that profession in the 1920s and 1930s. He was employed first in the family firm and later, in the 1930s, he left the firm and worked for Walter Zerfass founded his own company in Hintertiefenbach, now part of of Idar-Oberstein, Germany, from about 1964 Idar-Oberstein, Germany. After World War II, he augmented on, undoubtedly using the I.G.-Farben process.” his work by cutting and polishing hard materials for tech- Given the apparent logic, the explanation of- nical applications, such as jewel bearings for or fered by Nassau was widely accepted (see, e.g., water meters. Subsequently, in the early 1950s, he devel- oped processes for manufacturing layered used as Sinkankas, 1981; O’Donoghue, 2005, 2006). In a substitute for banded agate, leading to German patents addition to H. Espig, the inventor of the pro- published in 1951 and 1952. Also, in the early 1950s, Zerfass cess for growing IG Farben AG synthetic emer- met G. H. Jaeger (see footnote 2), and the two collaborated ald (Igmerald), there would have been a num- on several projects during that era. For instance, they co- operated in developing cutting and polishing methods for ber of people involved in the routine production technical ceramic products, an endeavour related to Jaeger’s of Igmerald in Bitterfeld, Germany, from 1935 work at that time for Degussa AG. They similarly began in to 1942. Such individuals, in turn, would have the early 1950s to partner on experiments for synthetic em- had internal knowledge of the process and could erald growth at Hintertiefenbach. After implementing their own production process, in 1963 they presented the first have moved to West Germany after World War II. synthetic emeralds resulting from these long-running efforts During a recent re-evaluation of the growth to the public. Other activities by Zerfass included cutting process applied by IG Farben at Bitterfeld and and polishing hard metal tools (e.g. knives for microtomes).

Synthetic Emeralds Grown by W. Zerfass 405 Feature Article

Figure 2: W. Zerfass developed a method for emerald Figure 3: Dr G. H. Jaeger, who worked with W. Zerfass in synthesis over the course of a decade, from approximately developing a synthesis technique for emerald, was an 1952 to 1962, and presented his first faceted synthetic inorganic chemist involved in the 1930s with emeralds to the public in 1963. Production of Zerfass processing and metallurgy. Later he focused on the synthetic emeralds continued in the 1960s and early development and production of oxide ceramics for Degussa 1970s on a small scale. Photo taken in approximately AG, now part of Evonik Industries AG. Photo taken in approx- 1970; courtesy of T. Zerfass. imately 1953–1954; © Evonik Industries AG. fass (hereinafter T. Zerfass), continues to reside in 2 G. H. Jaeger (1901–1974) studied natural sciences, espec- Idar-Oberstein and was interviewed by one of the ially chemistry, at the University of Frankfurt, Germany, authors (KS) in the course of this study. T. Zerfass from 1920 until graduating in 1924 with a dissertation on identified his father’s partner in developing the the analytical chemistry of nitrogen-bearing compounds. emerald synthesis technique as Dr Gustav Hein- In the curriculum vitae accompanying his thesis, he men- 2 tioned R. Nacken as one of his academic advisors. Nacken rich Jaeger (Figure 3). Jaeger was a chemist living and Jaeger also collaborated in the mid-1920s in Frank- in Neu-Isenburg, near Frankfurt, Germany. furt, and filed a patent application dealing with improve- Zerfass and Jaeger met by chance and there- ments to gemstone synthesis by the Verneuil technique. after cooperated for approximately two decades Based on this invention, German and British patent docu- ments by Nacken et al. were published in 1926 and 1927. (1952–1973) in the synthetic emerald project. Zer- Jaeger joined Degussa AG (Deutsche Gold- und Silber- fass was the practical partner, building the differ- Scheideanstalt, now part of Evonik Industries AG) in ent devices used in the experiments. Jaeger was Frankfurt in 1928, and eventually he left the company in the scientist, developing the various recipes for the 1959 because of health problems. From 1932 to 1938, he led operations at the branch of the company responsible fluxes and nutrients used to grow the synthetic for beryllium metallurgy and technology. Later he head- emeralds (T. Zerfass, pers. comm., 2015, 2016). ed production at Degussa of various technical ceramics, Corroborating this association, an internal doc- such as the so-called ‘Degussit’. Numerous German and ument from the Walter Zerfass gem-cutting com- international patents involving beryllium refinement and technology, dated in the 1930s and 1940s, named Jaeger pany, dated 1971, also named Jaeger as a partner as the inventor. From his involvement with Degussa, he in developing the process for synthetic emer- developed extensive expertise in the fields of beryllium ald growth (D. Jerusalem, pers. comm., 2015). chemistry and the processing of Be minerals.

406 The Journal of Gemmology, 35(5), 2017 Feature Article

Materials and Methods The present study is based on the examination of five faceted samples (0.24–1.02 ct) and two crys- tals (0.23 and 0.40 g) of Zerfass synthetic emeralds. Four samples came from the reference collection of the German Gemmological Association, Idar- Oberstein, and three were loaned by T. Zerfass. Refractive indices were measured on the fac- eted synthetic emeralds using a Topcon refrac- tometer, and the SG values of all seven rough and faceted samples (e.g. Figure 1) were meas- ured hydrostatically. All samples were examined with a gemmological microscope (magnification up to 100×), with and without immersion; also used was a Leica DM LM polarizing microscope, with a transmitted light source and magnification up to 1,000×. Photographic documentation of in- clusions at high magnification was accomplished with an Olympus DP25 digital camera with Olympus Stream Motion software (version 1.6.1). All seven Zerfass synthetic emeralds were chemically analysed by energy-dispersive X- Figure 4: These two Zerfass synthetic emerald crystals were ray fluorescence (EDXRF) spectroscopy using a grown using small seed plates of synthetic emerald that were suspended with gold wires in a special holder within a lithium Bruker Tracer III-SD portable unit equipped with molybdate flux. After the gold wires were removed from the an Rh anode (40 kV, 30 µA), a yellow filter (12 crystals, grooves where the wires originally rested remained mil Al + 1 mil Ti) and a 10 mm² peltier-cooled on the surface of the crystals (see arrows); the lower half of XFlash SDD system. The counting time was 30 s. the left crystal was sawn off for cutting purposes. Views are shown almost parallel to the c-axis of the crystals (above) and almost perpendicular to the c-axis (below). The left crystal Results measures approximately 6.0 mm in diameter on the basal Crystal Morphology face and 4.6 mm along the c-axis, and it weighs 0.23 g; the Of the two crystals examined (Figure 4), the larger right crystal measures about 6.8 × 5.7 mm on the basal face and 4.8 mm along the c-axis, and it weighs 0.40 g. Photos by one showed a short prismatic to thick tabular habit K. Schmetzer. consisting of a 12-sided prism and two basal faces. - First- and second-order hexagonal prisms m {101 - 0} and a {1120} were present in combination with as also seen in the larger crystal (see again Fig- the basal pinacoid c {0001}. Tiny polycrystalline ure 4). The smaller sample, however, had been material, most likely small synthetic emerald crys- sawn at a short distance from the groove, pre- tals grown by spontaneous nucleation, covered sumably to remove half of the piece for cutting. the prism faces. A groove traversed all prism faces, encircling the crystal (Figures 4 and 5). Gemmological Properties The smaller crystal also had a short prismat- The synthetic emeralds were slightly bluish ic form, with six dominant prism faces and one green in colour, displaying of blue- basal pinacoid. The six-sided prism also showed green parallel to the c-axis and green to slightly some smaller additional prism faces that would yellowish green perpendicular to the c-axis. The correspond to a 12-sided prism if fully devel- RIs of the faceted samples ranged from 1.558 to oped. The prism faces were again covered with 1.559 for ne and from 1.562 to 1.563 for no, with small prismatic synthetic emerald crystals (Figure a birefringence of 0.004. The SG values were 6), but these were somewhat larger than those between 2.65 and 2.66. These data are consist- seen on the other rough sample. Likewise pre- ent with information generally reported for flux- sent was a deep groove surrounding the crystal, grown synthetic emerald from various produc-

Synthetic Emeralds Grown by W. Zerfass 407 Feature Article

Figure 6: The smaller Zerfass synthetic emerald crystal is viewed here almost perpendicular to the c-axis. The prism faces are covered with small prismatic synthetic emerald crystals. The c-axis is almost vertical, and the length of the crystal along the c-axis is 4.6 mm. Photomicrograph by K. Schmetzer.

ers (see, e.g., Flanigen et al., 1967; Sinkankas, 1981; Henn, 1995). When the crystals and cut samples were viewed parallel to the c-axis with a microscope, a cellular pattern of residual flux was observed (e.g. Figure 7). This created a honeycomb-like Figure 5: The larger Zerfass synthetic emerald crystal is structure formed by residual flux concentrated viewed here perpendicular to the c-axis. The prism faces are along planes running through the synthetic em- covered with tiny synthetic emerald crystals. The groove in eralds in a direction parallel to the c-axis. When the centre circumscribing the prism faces was left by a gold examined in immersion (Figure 8), the three-di- wire; the wire had been used to suspend a small seed plate of synthetic emerald in the lithium molybdate flux. The c-axis mensional extension of the honeycomb pattern runs vertically, and the length of the crystal along the c-axis was evident. The individual cells of the pattern is 4.8 mm. Photomicrograph by K. Schmetzer. varied from nearly hexagonal to completely ir-

Figure 7: A cellular web-like pattern of residual flux is seen parallel to the c-axis of the Zerfass synthetic emerald crystals. The samples have diameters of approximately (a) 6.0 mm and (b) 6.8 × 5.7 mm. Photomicrographs by K. Schmetzer.

a b

408 The Journal of Gemmology, 35(5), 2017 Feature Article

a b c

Figure 8: Cellular honeycomb-like structures are formed by residual flux concentrated on planes traversing the synthetic emeralds in a direction parallel to the c-axis. Such structures were seen in all the faceted Zerfass synthetic emeralds, with the cells forming patterns that show a variety of sizes and shapes. Immersion; view parallel to the c-axis; field of view (a) 4.6 × 3.5 mm, (b) 3.5 × 2.6 mm and (c) 3.2 × 2.4 mm; photomicrographs by K. Schmetzer.

500 um 500 um 500 um

Figure 9: These images show details of the honeycomb-like structures observed in the Zerfass synthetic emeralds. These patterns are formed by tiny flux particles concentrated in various forms, ranging from almost planar faces running parallel to the c-axis to wispy veils with an entirely irregular arrangement. Transmitted light; view parallel to the c-axis; photomicrographs by H. A. Gilg.

200 um 200 um 200 um

Figure 10: At higher magnification, the tiny particles of residual flux in the Zerfass synthetic emeralds are shown to be formed by two-phase inclusions consisting of contraction bubbles and various components of the flux. Transmitted light; photomicrographs by H. A. Gilg. regular in shape (Figure 9). At higher magnifica- ways exactly planar and could even be slightly tion, the tiny particles of residual flux that formed inclined to one another. Strong colour zoning the pattern could be resolved (Figure 10), and was observed between the different growth lay- minute two-phase inclusions (residual flux with ers. The honeycomb pattern of six-sided to ir- contraction bubbles) were frequently apparent. regularly shaped cells formed by particles of re- When the rough and faceted samples were sidual flux caused the two crystals and some of viewed perpendicular to the c-axis, a layered the faceted samples to appear only translucent structure was observed with distinct bounda- when viewed perpendicular to the c-axis (again, ries that were more-or-less parallel to the basal see Figure 11), notwithstanding their rather good plane (Figure 11). The boundaries were not al- transparency when viewed parallel to the c-axis.

Synthetic Emeralds Grown by W. Zerfass 409 Feature Article

EDXRF Spectra

COM Mo Mo* * Cr

COM # * Mo # * * Cr # * # * c Counts Fe * # * * b Cr # * Fe * * Au * a Cr Au Au # Fe * * 5 10 15 20 25 30 Energy (keV)

Figure 11: Growth zoning combined with colour zoning is Figure 12: EDXRF spectra of Zerfass synthetic emeralds are seen parallel to the basal pinacoid in a faceted Zerfass shown for: (a) a crystal with the X-ray beam directed toward the synthetic emerald. Immersion; view perpendicular to the prism faces, (b) the same crystal with the X-ray beam directed c-axis, with the c-axis vertical; field of view 3.9 × 2.9 mm; toward a basal face and (c) a faceted sample. The spectra photomicrograph by K. Schmetzer. indicate Cr as the main colour-causing trace element, with traces of Fe, and also Mo as the main component of the flux. In addi- tion, the lower spectrum (a) shows signals for Au, derived from a Chemical and Spectroscopic Properties gold wire (now removed) that was originally used to suspend the The trace elements revealed by EDXRF spectros- seed plate for crystal growth. The peaks labelled with an asterisk copy showed a homogeneous pattern in all seven (*) are related to the X-ray tube (Rh) or to interactions with the samples (e.g. Figure 12). Chromium was the main instrument (Pd, Cu and Zn). Diffraction peaks are labelled #, and COM refers to the inelastic scattering of the incident radiation colour-causing trace element, with small traces of (Compton scattering). Fe also present. No V or Ni was detected. peaks in the EDXRF spectra in- dicate that the synthetic emeralds were grown team occurred independently. No person from from a Mo-bearing flux. Unexpectedly, char- the IG Farben staff involved either in develop- acteristic X-ray lines for Au were recorded for ing the Igmerald growth process (from 1929 to both rough samples, but only when analysed 1935) or in subsequently producing Igmeralds at with the X-ray beam aimed toward the prism Bitterfeld (from 1935 to 1942) could be identified faces and incorporating the surface grooves. as a potential co-worker of Zerfass. While docu- Gold was not detected when the beam was di- mentation does show that G. H. Jaeger had con- rected toward the basal faces of the two crystals, tact with Nacken during his years in Frankfurt in nor was it found in any of the faceted samples. the 1920s, no such connections to IG Farben staff -visible absorption spectra of sev- members at Bitterfeld have been demonstrated. eral previously examined Zerfass synthetic em- Nonetheless, consideration of the existing facts eralds (unpublished data of author KS) showed suggests a possible explanation for the errone- the typical Cr3+ spectrum of emerald without ous information published by Nassau (1976a,b): any remarkable features. This is consistent with It appears that Nassau might have misinterpret- chemical data of the present study, showing Cr ed what was said in the interview of Zerfass by as the dominant colour-causing trace element. Crowningshield. In the 1930s, when the break- through in emerald synthesis at Bitterfeld was announced (see Jaeger and Espig, 1935), Dr Max Discussion and Conclusions Jaeger was the director of the IG Farben chemical Connections Between IG Farben and Zerfass plant, including the gemstone branch at Bitter- Although similarities might exist between the feld. The first description of the ‘German synthet- process used by IG Farben for growing synthetic ic emerald’ by the Gemological Institute of Amer- emerald and the method later employed by Zer- ica (Anonymous, 1935) likewise mentioned the fass and Jaeger, all historical evidence indicates names ‘Jaeger’ and ‘Espig’. Thus, operating on the that technical developments made by the latter premise that the name Jaeger was given correctly

410 The Journal of Gemmology, 35(5), 2017 Feature Article

by Zerfass to Crowningshield, we might conclude to one that involved using seed plates and sep- that a conflation of family names could have led arating the nutrient into two components, with to the now largely discredited assumptions.3 quartz floating on top of the lithium-molybdate melt. Notably, they made these adjustments in- Production Technology dependently of other scientists dealing with em- From the results described above, it can be con- erald synthesis who adopted similar approaches, cluded that the production process applied by such as those formerly at IG Farben in Bitterfeld.4 Zerfass in Idar-Oberstein, which he developed A special holder for the suspended seed plates between 1952 and 1963 together with Jaeger, was placed between the ingredients at the bot- was based on flux-growth technology. Given the tom of the crucible and the quartz floating on outcome of our examinations, we could establish top of the melt. During early experiments, natural that synthetic emerald plates sliced parallel to the aquamarine or natural emerald was used to make basal face were used as seeds and suspended in seed plates. Such samples were not examined in a Mo-bearing flux for crystal growth. The combi- the present study, but a Zerfass synthetic emerald nation of the grooves seen traversing the prism described by Gübelin (1964a,b) containing nail- faces of the crystals and the traces of gold de- head spicules may represent this early work. The tected by EDXRF spectroscopy indicate that cir- primary production of the 1960s and 1970s, how- cumscribing gold wires were used to suspend the ever, was performed using oriented seeds cut seed plates in the flux. With that technique, the from synthetic emerald crystals obtained in the earlier growth experiments. With the crucible ar- crystals could grow freely in both directions par- rangement mentioned, especially the orientation allel to the c-axis of the crystal, but only limited and suspension of seed plates, crystal growth growth was observed perpendicular to the c-axis. was mainly in a direction parallel to the c-axis. The only colour-causing trace element identified A special furnace was used that was able to was chromium. The growth zoning parallel to the heat several crucibles at the same time. basal face suggests that several interruptions took In contrast to the IG Farben process, in which place in the growth process. nutrient was added to the bottom of the cruci- All of the foregoing conclusions drawn from ble every 2–3 days, the Zerfass process was per- observations of the rough and faceted samples formed without interruption for a period of about were confirmed by T. Zerfass, who has in-depth 2–3 weeks. Only then were the synthetic emeralds knowledge about the growth technology applied temporarily removed, and another run with addi- by his father and developed together with Jae- tional flux and nutrient was prepared. This sepa- ger. T. Zerfass also added further details about ration of the growth process into 2- to 3-week in- the growth process, as revealed in the follow- tervals was reflected in the zoning of the synthetic ing paragraphs, many of which were not de- ducible directly from the samples themselves. Similar to the IG Farben process, crystal growth 3 Since Dr M. Jaeger (1869–1938) and Dr G. H. Jaeger (1901– was performed in platinum crucibles, with the 1974) were both born in the city of Frankfurt on the Main, nutrient subdivided into two parts. Compounds the authors initially wondered whether they could be related (e.g. father and son or uncle and nephew). However, invest of Al, Be and Cr were placed in the bottom of -igations of various birth registers preserved at the Institut the crucible, and natural quartz crystals floated für Stadtgeschichte in Frankfurt failed to reveal any such on top of the lithium molybdate melt. No colour- familial relationship. Thus, there remains no proven con- nection, either professional or familial, between these two causing trace elements other than Cr (such as V chemists involved in the development of emerald synthesis. or Ni) were ever added by Zerfass and Jaeger to the nutrient. The method did not involve the 4 Because Zerfass and Jaeger started their work by following the techniques described by Hautefeuille and Perrey (1888, use of a temperature gradient within the crucible. 1890), rather than by undertaking experiments based on the The first experiments, performed in about 1952– successful work by Nacken (T. Zerfass, pers. comm., 2016), it 1953, started by reproducing the emerald synthe- is unlikely that Jaeger had obtained any information regarding sis described by French scientists in the late 19th Nacken’s emerald synthesis experiments of the mid-1920s. Nonetheless, it is possible that Nacken could have shown century (Hautefeuille and Perrey, 1888, 1890). By Jaeger examples of those flux-grown crystals. (For more 1956, Zerfass and Jaeger had altered their process details about Nacken’s work, see Schmetzer et al., 2016b.)

Synthetic Emeralds Grown by W. Zerfass 411 Feature Article

emeralds parallel to the basal faces. A proprietary first experiments in Bitterfeld, to 1973, when Zer- technique was used to avoid variable concentra- fass ceased production in Idar-Oberstein. tions of Cr in the melt within a single growth cy- Sources of direct information (i.e. provided by cle. In the final years of their partnership, Zerfass the producers) evidencing these developments is and Jaeger also performed experiments aimed at varied but limited. Certain aspects of IG Farben’s reducing the concentration of trapped flux par- process for Igmerald production were published ticles and obtaining larger and cleaner material. by Espig in the early 1960s, and further informa- Hence, the chronological history of the Zerfass tion was contained in internal IG Farben reports production can be summarized as follows. Experi- dated 1930, 1945 and 1946, likewise penned by ments in crystal growth took place from approxi- Espig, that have recently come to light (for de- mately 1952 to 1962, and the first faceted synthetic tails, see Schmetzer et al., 2016a). Nacken himself emeralds were presented to the public in 1963. Pro- never published regarding his emerald synthesis, duction continued on a small scale during the 1960s and only fragmentary accounts can be found in and early 1970s, and then terminated in ~1973. Allied government documents generated from ‘interviews’ with German scientists in 1945 and Comparison of the Processes Used for 1946 by American and British investigators after Emerald Synthesis by Nacken, Espig World War II (for details, see Schmetzer et al., (IG Farben) and Zerfass 2016b). Zerfass also did not formally document his The historical development of flux-grown synthet- work, but unpublished information was disclosed ic emerald in Germany occurred over the course to his son T. Zerfass (reported in this article). of six decades and involved three principal pro- Insights into growth technologies derived ducers: Nacken , IG Farben and Zerfass. The story from the foregoing sources proved to be con- can be traced from about 1910 or 1911, when a sistent with the examination of respective syn- precursor company of IG Farben performed the thetic emerald samples. Results of the authors’

Table I: Growth of synthetic emeralds by R. Nacken, IG Farben and W. Zerfass.* Production Nacken Type 1 Nacken Type 2 IG Farben Zerfass Schmetzer et al. Reference Schmetzer et al. (2016b) This paper (2016a) Time of production Mid-1920s 1935–1942 1963–1973 Flux Molybdate Molybdate-vanadate Molybdate Crucible Gold Platinum Silica plates, Quartz plates, Nutrient for SiO Quartz pieces, distributed in the melt 2 floating on the melt floating on the melt Nutrients for BeO Distributed in the melt At the bottom of the crucible and Al2O3 Cr- and Ni-bearing Chromophore(s) Cr-bearing compound compounds, alleged Cr-bearing compound yttrium oxide Synthetic emerald plate, cut parallel Type of seed Irregularly shaped natural beryl to the basal face Seeds suspended in the Suspension of Seeds placed below No suspension, seed freely distributed in the melt melt with gold wires and seed plate platinum baffles an additional holder Several growth cycles Several growth cycles of 2–3 weeks each of about 1 month with Growth cycles Several growth cycles without addition addition of nutrient of nutrient during the every 2–3 days cycle * Only the primary variants of the processes as finally developed are given. All of the techniques used a homogeneous temper- ature (no temperature gradient).

412 The Journal of Gemmology, 35(5), 2017 Feature Article

work on rough and faceted synthetic emeralds in the USA by Chatham in the early 1940s, and from all three producers are summarized in any such interest would have been augment- Table I. On a conceptual level, each producer ed by various discussions after 1945 involv- employed a process for growing synthetic em- ing Nacken’s experiments in emerald synthesis. erald based upon dividing the nutrient into two These various announcements may have en- components. Specifically, BeO, Al2O3 and col- couraged other researchers, such as the team work- our-causing ingredients were added to the melt ing at Linde’s research and development depart- separately from SiO2 (quartz or vitreous silica). ment, to grow synthetic emeralds. Being informed All three producers started with employing in principle about the success in emerald growth natural colourless beryl as seed material, but by IG Farben and Nacken in Germany and the only IG Farben and Zerfass transitioned to us- production by Chatham in the USA, Zerfass and ing synthetic emerald plates for seeds. The seeds Jaeger can be seen as following the same tradition. were suspended in a molybdate or molybdate- vanadate flux, primarily in gold or platinum References crucibles. For all three manufacturers, growth Anonymous, 1935. Synthetic beryl, with notes by Prof. then proceeded through multiple cycles. In Dr. Karl Schlossmacher, B.W. Anderson and Georg the IG Farben process, additional nutrient was O. Wild. Gems & Gemology, 1(10), 281–286. Crowningshield R., 1970. Developments and highlights added to the bottom of the crucible every 2–3 at GIA’s lab in New York: Zerfass synthetic emerald. days. This method, however, had the disadvan- Gems & Gemology, 13(5), 162. tage of frequently interrupting the process and Eppler W.F., 1964. Ein neuer synthetischer Smaragd. causing different equilibria and concentrations Deutsche Goldschmiede-Zeitung, 62(3), 183–184. of nutrient within the melt. Further develop- Flanigen E.M., Breck D.W., Mumbach N.R. and Taylor A.M., 1965. New hydrothermal emerald. Gems & ments instigated by Zerfass avoided this prob- Gemology, 11(9), 259–264, 286. lem, but the details of the technique have not Flanigen E.M., Breck D.W., Mumbach N.R. and Taylor been disclosed by his son to the present authors. A.M., 1967. Characteristics of synthetic emeralds. Nacken and Zerfass used only Cr-bearing com- American Mineralogist, 52(5–6), 744–771. Gübelin E.J., 1964a. Two new synthetic emeralds. pounds as colour-causing trace elements. Espig, in Gems & Gemology, 11(5), 139–148. contrast, added carbonate to the melt, and Gübelin E.J., 1964b. Zwei neue synthetische Smar- this component was responsible for the desired agde. Zeitschrift der Deutschen Gesellschaft für slightly yellowish green colour of the Igmeralds, Edelsteinkunde, No. 47, 1–10. as compared to natural and synthetic emeralds Hautefeuille P. and Perrey A., 1888. Sur la reproduc- tion de la phénacite et de l’émeraude. Comptes without Ni. Although yttrium oxide was also add- Rendus Hebdomadaires des Séances de l’Académie ed by Espig as a purported colour-causing ingre- des Sciences, 106, 1800–1803. dient, any potential influence on colour remains Hautefeuille P. and Perrey A., 1890. Sur les combinai- unclear; samples showing traces of Y by EDXRF sons silicatées de la glucine. Annales de Chimie et de Physique, 6. Série, 20, 447–480. spectroscopy and those without any detectable Y Henn U., 1995. Edelsteinkundliches Praktikum. Gem- did not display any noticeable difference in colour. mologie: Zeitschrift der Deutschen Gemmologi- For those Nacken synthetic emeralds grown from schen Gesellschaft, 44(4), 3–112. vanadate-molybdate fluxes, V may make a small Jaeger M. and Espig H., 1935. Der synthetische Sma- contribution to the otherwise Cr-based colour, ragd. Deutsche Goldschmiede-Zeitung, 38(35), 347–349. similar to that exhibited by natural emeralds from Nassau K., 1976a. Synthetic emerald: The confusing various sources, such as those from . history and the current technologies. Journal of With IG Farben’s announcement in 1935, it Crystal Growth, 35(2), 211–222, http://dx.doi.org/ became public knowledge that growing syn- 10.1016/0022-0248(76)90172-x. thetic emeralds of facetable size was possible. Nassau K., 1976b. Synthetic emerald: The confusing history and the current technologies, Part 1. Lapi- Although details of the growth technology used dary Journal, 30(1), 196–202. by IG Farben were not disclosed until the early Nassau K., 1976c. Synthetic emerald: The confusing 1960s, the mere presentation of these first fac- history and the current technologies, Part 2. Lapi- eted samples may have stimulated interest with- dary Journal, 30(2), 468–472, 488–492. O’Donoghue M., 1980. Characterization of crystals in the research community. A similar effect was with gem application. Progress in Crystal Growth created some years later by the presentation of and Characterization, 3(2–3), 193–209, http:// the first faceted synthetic emeralds produced dx.doi.org/10.1016/0146-3535(80)90019-2.

Synthetic Emeralds Grown by W. Zerfass 413 Feature Article

O’Donoghue M., 2005. Artificial Gemstones. N.A.G. ment and properties related to growth technology. Press, London, 294 pp. Journal of Gemmology, 35(3), 224–246, http:// O’Donoghue M., 2006. Gems: Their Sources, Descrip- dx.doi.org/10.15506/JoG.2016.35.3.224. tions and Identification, 6th edn. Butterworth- Schmetzer K., Gilg H.A. and Vaupel E., 2016b. Synthetic Heinemann, Oxford, 470–530. emeralds grown by Richard Nacken in the mid- Schlossmacher K., 1963. Eine neue Smaragdsynthese. 1920s: Properties, growth technique, and historical Zeitschrift der Deutschen Gesellschaft für Edel- account. Gems & Gemology, 52(4), 368–392, http:// steinkunde, No. 43, 27–29. dx.doi.org/10.5741/GEMS.52.4.368. Schmetzer K., Gilg H.A. and Vaupel E., 2016a. Synthetic Sinkankas J., 1981. Emerald and Other . Chilton emeralds grown by IG Farben: Historical develop- Book Co., Radnor, Pennsylvania, USA, 665 pp.

The Authors Acknowledgements Dr Karl Schmetzer The synthetic emeralds grown by W. Zerfass D-85238 Petershausen, Germany in cooperation with G. H. Jaeger were kindly Email: [email protected] loaned by Dr T. Zerfass and by Dr U. Henn (Ger- Prof. Dr H. Albert Gilg man Gemmological Association). T. Zerfass also provided valuable information about the Lehrstuhl für Ingenieurgeologie, Technische history and production technology of his father’s Universität München, D-80333 Munich, emerald synthesis. We also appreciate the as- Germany sistance of D. Jerusalem of Idar-Oberstein in Prof. Dr Elisabeth Vaupel providing historical insights. Forschungsinstitut für Wissenschafts- und Technikgeschichte, Deutsches Museum, D-80538 Munich, Germany

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414 The Journal of Gemmology, 35(5), 2017

Feature Article

Rethinking Laboratory Reports for the Geographical Origin of Gems

Jack M. Ogden

The proliferation of gemmological laboratory reports and the need for transpar- ency to best protect against litigation suggest that some gem-testing labora- tories should consider changes in the wording and content of their geographi- cal origin reports. Based on the author’s recent broader study of the legal aspects of the opinions provided by experts in the field of art and antiques, the main proposals presented here are that statements of opinion rather than fact should be clearly expressed as such where they are presented on a report, rather than relegating all mention of ‘opinion’ to the ‘terms and conditions’, and that the basic nature of the observational or analytical evidence on which any opinions are based should be noted. In addition, a laboratory might use- fully provide some indication of the level of confidence in its opinion.

The Journal of Gemmology, 35(5), 2017, pp. 416–423, http://dx.doi.org/10.15506/JoG.2017.35.5.416 © 2017 The Gemmological Association of Great Britain

Introduction in the unenviable position of having to action the In a recent law journal article, the present author closing of Gem-A’s lab in 2008 when he was CEO considered opinions in the art and antique world of Gem-A. Those wanting more of the legal back- from a legal perspective and suggested how the ground are directed to Ogden (2016). rather woolly concept of ‘opinions’ might be made Numerous authors in the past have considered more objective and therefore more useful to those the challenges that confront gemmological labo- who rely on them, including the courts (Ogden, ratories issuing reports and their need to balance 2016). This article looks more briefly at opinions scientific prudence with the demands of the gem provided in gemmological testing and grading re- trade, particularly with regard to geographical ori- ports, and proposes some ways to improve their gin determination (e.g. Hänni, 1994; Nyfeler, 2006; helpfulness and transparency. This is written from Krzemnicki, 2007; Rossman, 2009). In addition, the the point of view of someone with recent experi- actual processes and procedures of gem testing ence in art law1, and who has had a long asso- within a laboratory have been described at length ciation with gem labs as an observer—from being in this and in other gemmological journals. on the committee overseeing the lab run by the Origin reports have become a prominent part Diamond, Pearl and Precious Stone Section of the of the gem trade, particularly for high-end stones London Chamber of Commerce (the forerunner of (e.g. cover of this issue and Figure 1). They aim to the Gem-A laboratory) in the early 1970s to being provide support for the seller and reassurance for the buyer, and, as is often observed, some gems 1 The author has had a long-term interest in art law and was seem to be sold as much on the basis of their ac- awarded a Diploma in Art Profession Law and Ethics (with companying paperwork as on their appearance distinction) by the Institute of Art Law, London, in 2014. (Figure 2). Against this background, it is timely

416 The Journal of Gemmology, 35(5), 2017 Feature Article

report because of the lack of precision. There has been some education of laboratory users about the way in which labs reach their conclusions, such as SSEF’s Standards & Applications for Diamond Re- port/Gemstone Report/Test Report (1998), but little to help the user gauge how much confidence the laboratory might have in its report. A laboratory report offering the opinion that a particular sap- phire is from Kashmir (e.g. Figure 3), say, could imply anything from the lab’s absolute conviction that it is from that cherished source to a consensus among lab employees that on balance it is more likely to be Kashmir than not (e.g. Hänni, 1990). A consensus approach such as this is not unusual, particularly with diamond grading. If two employ- ees in a lab have slightly different views, they will typically ask a third for their opinion and go with the majority. It is essential that the nature of a lab report as an opinion must be made absolutely clear to all who are likely to rely on it, but if we accept that laboratories would be delusional to as- sert that they were equally confident in all their opinions, do the users of their reports have some right to know how convinced those labs are about Figure 1: This with a 30.08 ct sapphire was sold at their opinion? auction (Bonhams, London, 30 April 2014, lot 186) and Opinions presented in gem-testing reports are was accompanied by three lab reports that gave two dif- of course nothing more nor less than educated ferent geographical origin opinions—Sri Lanka and Burma guesses or a consensus of educated guesses. (Myanmar). Photo © Bonhams, used with permission. If they were more than educated guesses they would be facts. Referring to details on gem lab reports, particularly origin statements, as educated to consider whether the uncertainty often inher- guesses is not a new thing; a previous example ent in such reports is always presented clearly is mentioned in an editorial in Gems & Gemology enough to those who rely on them. This is par- (Liddicoat, 1990). The education for the guesses ticularly important with ‘origin’ reports, which can is provided by a range of factors—from precise have a huge impact on prices. Some laboratories and replicable scientific analysis to experience and are scrupulously cautious here with their wording even gut feelings—and so, if the report presents and its prominent placing; others are less so. an opinion rather than a provable fact, it will be This article discusses the nature of opinions based on a combination of objective and subjec- on geographical origin reports, the objective and tive elements. For as long as there is a subjective subjective factors leading to an expression of element, then report conclusions necessarily will opinion of origin—and the levels of confidence not be constant from one laboratory to another. in that opinion—and then considers extended li- This is not a new observation. For example, Hain- ability and trade expectations before giving rec- schwang and Notari (2015) pointed out that where ommendations for initial steps toward improving lab reports are based to some extent on “the opin- the transparency and usefulness of such reports by ion of the analyst and not only on scientific evi- proposing changes in their wording and content. dence…the results of a specific stone may vary to a certain degree from laboratory to laboratory”. The Nature of Opinions Gemmological laboratories are usually careful to Objective and Subjective Elements state that their reports present opinions. This pro- In the interests of transparency for the user of vides a level of protection against litigation for the the report and for protection against litigation lab but can be of limited comfort to the user of the for its issuer, it is reasonable to suggest that the

Rethinking Gem Lab Reports 417 Feature Article

Figure 2: A shop window in New York’s jewellery district demonstrates the significance currently given to lab reports. Photo by J. M. Ogden, November 2016. objective facts and the subjective interpretations colour terminology. The treatment of a gem may derived from them should be distinguished in the be an observable fact (a visible laser drill hole report. Even this is not as simple as it sounds. in a diamond, for example) or a subjective infer- Some aspects are obviously facts, such as the ence based on observation or analysis. Neverthe- weight and shape of a gem, but even here names less, it should be possible to distinguish between of shapes or the classifications of girdle thick- the objective aspects that could be checked and nesses, say, are not standardized any more than is replicated by another laboratory, and the deduc- tions by the laboratory from observation or in- ferred on the basis of past experience or defined Figure 3: Two examples are shown of the sections on 'Origin' using non-standardized terminology. on gemmological laboratory reports, for a 10.33 ct sapphire This suggestion of a distinction between the sold by Christie’s in Hong Kong in 2015. The Christie’s catalogue described both reports as “stating that the 10.33 objective and the subjective is not a novel pro- sapphire is of Kashmir origin”. The sapphire fetched posal; it is already laid down for the handful of $2.5 million. gemmological laboratories that are accredited un- der International Standard ISO/IEC 17025 (2005). International Standards lack legal weight in most jurisdictions, but they would usually be taken to represent best practice. This particular standard is aimed primarily at testing laboratories where the data collected are measurable facts, but it rec- ognizes that reports may include opinions based on those facts, and so in Section 5.10.5 it states that “Opinions and interpretations shall be clearly marked as such in a test report.” It goes on to

418 The Journal of Gemmology, 35(5), 2017 Feature Article

say that “When opinions and interpretations are through the files of photocopies of lab reports at included [in a report], the laboratory shall doc- any major jewellery auction preview, viewed by ument the basis upon which the opinions and public as well as trade buyers, to realize that it interpretations have been made.” It could be ar- is time for more up-front—literally—transparency gued that this latter clause means that the labora- and honesty. We can note that in its recent formal tory should retain this documentation in its files request for public views on ‘terms and conditions’ and not necessarily pass it on to the client, but in relating to consumer products, the UK govern- the interest of transparency there are good rea- ment has expressed its view that the key terms in sons to suggest that in addition to distinguishing such conditions should be ‘upfront and bold’ (De- between the analyses or measurements a labora- partment for Business Innovation & Skills, 2016). tory has made on a gem and the deductions it One cannot argue that the ‘opinion’ nature of a lab has derived from these, it should provide some report is not a key aspect. indication on the report of how the latter were It is growing practice for gemmological labo- inferred from the former. ratories to accompany a report on an important Indeed, in the UK at least, we can find some gem with supplementary documentation that can legal support for this. In a very different sort of range from a letter to a glossy book. Such an context, Lord Justice Stuart-Smith stated: “I do offering about an emerald, say, might praise its not think guesswork, educated or otherwise, is size, quality and Colombian origin, but among sufficient to discharge the burden of proof, es- the glossy photos of sunsets over Muzo, compari- pecially when he [the expert] does not indicate sons with the green in a Renoir painting and sto- what evidence he relies upon as educating his ries of Cleopatra and conquistadors, there might guess” (Vernon v Bosley, 1996). As things stand, be little sign of a clear statement that the Colom- a sapphire might be sold at a very high price as bian origin of the gem in question is merely an ‘Kashmir’ on the basis of evidence less persuasive opinion. As a side note, this author repeats a plea than would be needed to convict someone of made before (Ogden 2012a): that labs should ap- stealing it. This practice of including the data on ply the same level of academic rigour to these which the opinion is based in a laboratory report glossy dossiers as they would to the publication has been termed a “justified report” (Segura et of their gemmological research. al., 2015). Justification in this way, as defined in the International Standard 17025 cited above, is Levels of Confidence particularly applicable to opinions of origin for gems where, in the words of Bui et al. (2012), Even if lab reports start becoming more open about “origin determination is sometimes more akin to the opinions they provide, along the lines of the branding than science”, although they ignore the wording proposed for the Kashmir sapphire ex- point that ‘science’ is itself a combination of ex- ample above, they still will not have solved the periment, observation, interpretation and theory. problem of the inherent fuzziness of the word ‘opinion’. Some gems are trickier than others to characterize and some easier, all for a wide vari- Clear Expression of Opinion ety of reasons: from the individual nature of the In the spirit of International Standard 17025, and gem, to laboratory experience or rigour of the thus again arguably best practice, it would make stone reference database, to fortuitous availability things clearer if all gem labs clearly stated that of up-to-date published research. So, would it be opinions are simply opinions where they are pre- reasonable for the user of a report to have some sented in a report, and not relegated to some gen- indication as to how much confidence a laborato- erality about it all being an opinion in the typically ry has in its opinion? From the report user’s point small print of the ‘terms and conditions’, sometimes of view—or the lawyer’s, if a dispute ever came even on the reverse of the report. This means stat- to court—a useful question to the report’s sig- ing something like, ‘Based on the chemical con- natory would be, “Are you personally convinced stituents of the sapphire, the measured spectral that the gem is from Kashmir (say) or merely be- features and its internal characteristics, it is this lieve that it is probably so?” laboratory’s opinion that it comes from Kashmir’, Quantification of overall confidence that the rather than simply saying ‘Origin: Kashmir’ with sapphire is from Kashmir is problematic. Courts a generalized disclaimer about ‘opinions’ tucked must often undertake such assessment to ap- away on the side or back. One only needs to leaf portion blame or damages on the balance of

Rethinking Gem Lab Reports 419 Feature Article

probability, sometimes quoted as a percentage, they are not. This would be ideal where the re- when confronted by conflicting evidence with no sults of chemical analysis could be compared with means of determining the truth. Court pragma- a robust database of reference material. There are tism is different from market reality, however, and good arguments for statistical results, whether ex- besides, laboratories could not consistently cal- pressed numerically or graphically, to be noted on culate overall likelihood. But just because numer- a gem report as part of the supporting evidence ical quantification of a lab’s overall confidence in for a stated opinion.2 If the trace-element ratios an opinion is unrealistic, it does not mean that indicate an 85% chance that a sapphire is from all quantification is unwarranted. When there is Kashmir, it seems fair—and certainly in the spirit clear, objective data from a gem, such as trace- of International Standard 17025—for the end- element ratios and a large and robust database user to be told. It helps explain one of the criteria of comparisons, deductions can be made. Plotted by which the lab justifies its final opinion. Chemi- charts can give a graphical indication of groupings cal analysis is seldom the sole criterion; various and overlaps (e.g. Figure 8 of Wang et al., 2016, internal characteristics will help identify origin, at www.gem-a.com/component/edocman/3233- sometimes fairly conclusively, and often colour wang-additional-plots-to-accompany-figure-8/ will give clues. A combined approach will typi- download?Itemid=), although these are com- cally provide a more certain indication of origin monly constrained to two dimensions with two than chemical analysis alone, but even so can or three variables, while multivariate statistics can the user of a report claim a right to be told if the generate probabilities expressed in percentages objective analytical data, in effect, showed a 15% with definable margins of error. chance that the gem was not from Kashmir (see There is a good parallel here with the Antique Ogden, 2012b)? Plate Committee of the Worshipful Company of Of course, there is a further layer here: the , London, which has been operating confidence a laboratory has in the database or for nearly 80 years. A piece of antique silver sub- reference collection upon which it relies. The mitted to this committee for verification is ana- Gemological Institute of America (GIA) classifies lysed, the results are compared with a huge data- its laboratory reference collection according to base of analyses, and the likelihood of a certain the confidence it has in the given origin, ranging date range is expressed as percentages. Thus, the from certainty with gems collected in the mine by computations might show that a purported Geor- their own employees to the far less reliability of gian silver coffee pot has an 84% likelihood of the stated origin of gems purchased in the market being pre-circa 1830, an 11% likelihood of being (Pardieu, 2009). Only a few laboratories, however, between 1830 and 1899, and a 5% chance of be- have the resources to build rigorous sample data- ing 20th century or later. No one pays top price bases. ‘Objective’ statistics based on factors such for a Georgian coffee pot with a 16% chance it as trace-element ratios are only as reliable as the is fake, so the Antique Plate Committee mulls comparative data to which the lab has access. over the analysis implications in the light of their expertise and experience regarding style, tech- Extended Liability nique, patina and so on, and then states its over- all opinion—alongside noting the 84% probabil- The growing profusion of supplementary docu- ity as generated by the statistical calculations of mentation aimed at the ultimate buyer says a lot the analysis results. about who the labs see as their end-user, even This author is not aware of published informa- though reports might state that they are solely for tion about multivariate statistics being used this the commissioning client—usually a gem dealer, way in gem labs, although it is hard to imagine auction house or jeweller. Labs know that con- sumers often rely on reports and, in a wider con- text, might work with consumer protection agen- 2 The challenge of providing useful information in reports cies to help safeguard the public. They also have without disclosing intellectual property has been noted by some legal responsibilities further down the line, the author (Ogden, 2016). There can be a balance, not- certainly in the UK. If the lab knows or should ing sufficient background to show due diligence without reasonably be expected to know that their report revealing proprietary methods. The situation if a dispute comes to court can be more problematic, especially since will be relied upon by a third party, their liabil- those best able to gauge the validity of an approach are ity will generally extend to that party. There is the very competitors from whom a lab may wish to hide it. UK case law on this, although nothing specific to

420 The Journal of Gemmology, 35(5), 2017 Feature Article

gems, but for equivalent situations such as prop- for ongoing discussion. Labs differ in the equip- erty surveys and company valuations (Ogden, ment and experience they have, and one might 2016). Labs are potentially liable to third parties be far more accomplished with one type of gem or classes of third party that they know, or should than another. reasonably expect, are likely to rely on their re- port. Whatever the original intention of lab re- ports, labs now know full well that their reports Trade Expectations often will play a significant role in both market- The gem trade’s use of lab reports brings us back ing and purchasing decisions. Some of the dos- to the practicalities. There is no scientific reason siers and other supplementary documents issued not to be more open and transparent about lab re- by gem labs are so blatantly an endorsement for ports being an educated guess, and likewise there a gem that this author wonders if they might even is no reason for them not to include something be subject to advertising legislation. about the data and reasoning that formed the basis We have talked about the evidence that sug- of the stated opinion. There are strong ethical and gests what a gem is. What about contrary evidence? probably even legal reasons why they should. The There is legal support, in the UK anyway, to the main obstacle is the trade. Those who commission view that if the seller is aware of any significant the reports ideally want black-and-white answers: negative opinions about a gem, the buyer should the origin of the sapphire, say, stated as unequiv- be advised of this. (For a case involving negative ocally as possible. Just consider the indignation, opinions on antique porphyry vases, see Thomson even anger, that can greet an ‘undeterminable’ lab v. Christie Manson & Woods Ltd and others, 2005.) verdict on a stone. However, if a lab is to be genu- This probably means that if the laboratory is aware inely independent and aware of its responsibilities of negative or less-than-wholly-supportive aspects to all who are likely to rely on the report, it should of their opinion, the user of the report might have not let its scientific principles be subverted by the a right to be told. On this basis, the user of the unrealistic expectations of the gem trade. Modern report probably has a right to know if the data or gemmology is deeply complex and must attempt observations leading to a ‘Burma’ origin for a sap- to keep its head above the waters of the flood of phire left room for significant doubt, or if two of gem treatments, synthetics and origin challenges. the gemmologists in the lab thought it was from But laboratories tread a difficult path. As one Myanmar but another indicated Sri Lanka. former lab director has said, if gem laboratories Also, the not-uncommon practice for a dealer are too cautious in their reports, they lose cus- to get more than one lab report for the origin of tomers; if they are overconfident, they lose cred- a sapphire, say, and retain any that say Kashmir ibility (H. A. Hänni, pers. comm., 2017). Labs are and dispose of the rest, is likely to be illegal rather businesses and costly to run, so there must be than just unethical. This selective presentation of a balance, but the overriding factor must surely lab reports in the trade has been countered by be the best interests of those who rely on the re- the growing practice for major auction houses to ports. The boards that run the labs might also be list the findings of different gem labs in their cat- warier about expressing uncertainty than those alogues, even if they disagree. For example, an working in them, but times are changing. auction of fine jewellery held in London in 2014 included a ring set with an important sapphire Every industry today is awash with the need weighing 30.08 ct (again, see Figure 1; Bonhams, for laboratory reports, from contaminants in baby 2014). It was accompanied by reports from SSEF powder to gold wreaths. In the and The Precious Stone Laboratory (London) giv- art and antique world, perhaps closest in con- ing a Sri Lankan origin, as well as a report from cept to gem lab reports, it is increasingly normal the Gübelin Gem Lab expressing the opinion that for reports to include tables of analyses, details it was from Burma. This openness in providing all of methods of manufacture and signs of age, of- three reports is the result of legal advice and an ten with photomicrographs and, of course, the indication of the sort of transparency, realism and relevant expert’s overall view, which necessarily honesty that buyers should be able to expect from includes the input of his or her ‘experienced eye’. all in the trade. How buyers might be expected to With a carefully thought-out workflow, the addi- know how much confidence they can place in the tion of analytical data and photos (e.g. Figure 4) individual laboratories is a problem and a matter does not greatly increase the time taken to pro-

Rethinking Gem Lab Reports 421 Feature Article

Figure 4: This lab report provides an example of including photomicrographs to support an opinion of a stone’s geographical origin—in this case, a Burmese ruby. Courtesy of Dr Jayshree Panjikar. duce a report. After all, the lab is keeping these for and impact on the trade is long overdue. There records anyway. are various industry bodies that could spearhead However, with a more ‘justified’ gem lab report, this, and even a new International Standard is this author is not suggesting documenting every in- perhaps not unrealistic. With the growing use of clusion, say, but rather providing an overview of reports and the legal liabilities of labs, such dis- the range of observations or tests that were signifi- cussions are surely essential. This author suggests cant in reaching the conclusions presented, along two initial steps: with a statistical representation of data where rel- • When conclusions presented in a lab re- evant. This sort of report will not necessarily give port are opinions, not facts, they should sufficient detail for the reader to gauge how much be clearly expressed as such at the point confidence he or she should place in the report, but where they are presented. it should be worded in a way to indicate broadly • Reports should briefly explain the nature how confident the lab is in its opinion. More justi- of the observations and analyses on which fied laboratory reports might not reduce the issu- their conclusions are based, where possi- ing of conflicting reports by different labs, but they ble including relevant photomicrographs, might better allow the users of those reports to un- analyses or statistical information. derstand why different conclusions were reached. Another step would be to realize that use of the word ‘probably’ in a report can be a sign of wisdom rather than weakness. Conclusions It might well be that some gemmological labo- A serious discussion of a way forward in the con- ratories decide their future is best served as the text of gemmological lab reports, and their value marketing arm of the gem trade. That is their

422 The Journal of Gemmology, 35(5), 2017 Feature Article

choice; there is nothing wrong with the gem- Nyfeler D., 2006. The limitations of origin determination. mologist as poet, but they cannot then pretend Jewellery News Asia, No. 264, 56–62. to the trade, and the trade cannot pretend to their Ogden J., 2012a. Editorial: Romancing the stone. Gems customers, that they represent an independent, &Jewellery, 21(4), 1. detached service. If all gem lab reports become Ogden J., 2012b. Quantifying an opinion. Gems& more open about the inherent uncertainties be- Jewellery, 21(1), 44. Ogden J., 2016. A matter of opinion. Art, Antiquity hind many opinions, fine gems might begin again and Law, 21(2), 269–279. to be sold on the basis of their beauty and indi- Pardieu V., 2009. Annex 1: Introduction to GIA’s viduality rather than on the basis of paper. A wider sample collecting protocols. In Concise Field and more realistic understanding of the subjective Report. Volume 1: Pailin, Cambodia (Dec 2008 – content of lab reports would mean also an under- Feb 2009), GIA Laboratory, Bangkok, Thailand, standing that labs should be able to change their www.giathai.net/pdf/Public_Report_PR01_Pailin. opinions without this being viewed as a sign of pdf, accessed 23 February 2017. incompetence or ignorance. Information, experi- Rossman G.R., 2009. The geochemistry of gems and its ence and technology develop. As the 18th century relevance to gemology: Different traces, different moralist Joseph Joubert said: “Those who never prices. Elements, 5(3), 159–162, http://dx.doi.org/ retract their opinions love themselves more than 10.2113/gselements.5.3.159. they love truth.” Segura O., Fritsch E. and Droux A., 2015. Justifying gem testing reports: The way labs can inform their customers. InColor, No. 28, 24–26. SSEF Swiss Gemmological Institute, 1998. Standards & References Applications for Diamond Report/Gemstone Report/ Test Report. SSEF, Basel, Switzerland, 118 pp. Bonhams, 2014. Lot 186: A Sapphire and Diamond Thomson v Christie Manson & Woods Ltd and others, Ring. www.bonhams.com/auctions/21556/lot/186, 2005. EWCA Civ 555, England and Wales Court of accessed 23 February 2017. Appeal, Civil Division, 12 May. Bui H.A.N., Fritsch E. and Rondeau B., 2012. Vernon v Bosley, 1996. EWCA Civ 1217, England Geographical origin: Branding or science? InColor, and Wales Court of Appeal, Civil Division, 13 No. 19, 30–39. December. Department for Business Innovation & Skills, 2016. Wang H.A.O., Krzemnicki M.S., Chalain J.-P., Lefèvre Terms & Conditions and Consumer Protection P., Zhou W. and Cartier L.E., 2016. Simultaneous Fining Powers: Call for Evidence. Department for high sensitivity trace-element and isotopic analysis Business, Innovation and Skills, London, 45 pp. of gemstones using laser ablation inductively Hainschwang T. and Notari F., 2015. Standards and coupled plasma time-of-flight mass spectrometry. protocols for emerald analysis in gem testing Journal of Gemmology, 35(3), 212–223, http:// laboratories. InColor, special issue from the 1st dx.doi.org/10.15506/jog.2016.35.3.212. World Emerald Symposium, December, 106–116. Hänni H.A., 1990. A contribution to the distinguishing characteristics of sapphire from Kashmir. Journal of Gemmology, 22(2), 67–75, http://dx.doi.org/10. The Author 15506/JoG.1990.22.2.67. Dr Jack M. Ogden FGA Hänni H.A., 1994. Origin determination for gemstones: Striptwist Ltd., 55 Florin Court, Charterhouse Possibilities, restrictions and reliability. Journal of Square, London EC1M 6EU Gemmology, 24(3), 139–148, http://dx.doi.org/10. E-mail: [email protected] 15506/JoG.1994.24.3.139. International Standard ISO/IEC 17025, 2005. General Requirements for the Competence of Testing and Acknowledgements Calibration Laboratories, 2nd edn. International The author is grateful to Prof. Dr Henry A. Organization for Standardization and International Electrotechnical Commission, Geneva, Switzerland, Hänni (GemExpert, Basel, Switzerland) for May 15, 36 pp. many helpful suggestions for improvements to Krzemnicki M.S., 2007. Determining the origin of this article, to the other anonymous review- gemstones: Challenges and perspectives. InColor, ers of its first draft, and to Dr Daniel Nyfeler Spring, 6–11. (Gübelin Gem Lab, Lucerne, Switzerland) for Liddicoat R.T., 1990. The country of origin question. useful conversations on this subject. Gems & Gemology, 26(4), 247.

Rethinking Gem Lab Reports 423 Gemmological Brief

Fake Pearls Made from Tridacna gigas Shells

Michael S. Krzemnicki and Laurent E. Cartier

Five non-nacreous ‘pearls’ that allegedly came from Tridacna gigas (giant clams) were studied for this report. Our observations revealed that none of them were pearls, but instead they had been manufactured from Tridacna clam shell. The identification of such imitations is in most cases straightfor- ward, and is mainly based on their characteristic layered structure observed in reflected light and with transmitted fibre-optic illumination. Our results are compared with recent reports of other such fake pearls that are often wrongly described as being genuine natural pearls.

The Journal of Gemmology, 35(5), 2017, pp. 424–429, http://dx.doi.org/10.15506/JoG.2017.35.5.424 © 2017 The Gemmological Association of Great Britain

Introduction Tridacna Clams and Their Pearls Pearls inspire the imagination of mankind, as Tridacna clams (Tridacninae subfamily) are they have represented status, good fortune and among the largest living bivalve molluscs, with a wealth since historic times. Therefore, it is no sur- shell diameter up to 110 cm (Sarasin, 1904; Rose- prise that, even today, exceptionally large pearls water, 1965). Inhabiting shallow coastal waters of attract much interest among the public (even the Indo-Pacific region (Rosewater, 1965), these though they are not nacreous). Occasionally re- species are nowadays among the most endan- ports on such objects appear in popular news gered clams and are protected by the Convention media, in which they are commonly and correctly on International Trade in Endangered Species described as formations from the Tridacna clam (CITES, 2016). Their white shell is massive and (e.g. Tridacna gigas). A single account from a lo- thick, and shows a characteristic and attractive cal newspaper may be multiplied by press agen- wave-like cross-section. As such, the shell has cies, so that a story based on just one pearl is been used for adornment in native cultures and then covered in many newspapers and websites, historically as fonts (vessels containing holy wa- thus making its way into worldwide headlines. ter) in Catholic churches throughout Europe (e.g. Due to such recent media coverage, the au- Saint Sulprice in Paris, France: Figuier, 1868, p. thors’ laboratory is being confronted with numer- 148; Kunz and Stevenson, 1908, p. 76). ous requests to analyse similar non-nacreous ‘gi- The presence of symbiotic single-celled dino- ant pearls’. This article documents the results of flagellate algae (zooxanthellae) in the mantle tis- our testing on five such items at SSEF (Figure 1), sue of Tridacna clams not only results in a col- all of which proved to be fake pearls that had ourful appearance of the living animal, but also been cut and polished from Tridacna clam shell. is regarded as the reason for the growth of the

424 The Journal of Gemmology, 35(5), 2017 Gemmological Brief

Figure 1: These five fake pearls (samples A–E), all cut from the shell of giant

A clams, were studied for this report. The largest item is 27 cm in diameter and

B weighs 6.8 kg. Photo by V. Lanzafame, © SSEF.

E C D

massive calcium carbonate shells of these spe- Samples and Methods cies (Dame, 2011). For this study, we investigated five samples (speci- Pearls, blister pearls (i.e. those attached to mens A–E, Figure 1) submitted to SSEF by one the inner wall of a shell) and blisters (i.e. in- client who reported them to be Tridacna pearls ternal protuberances of the shell caused by the originating from Palawan, an island in the eastern intrusion of foreign bodies between the mantle Philippines. The samples ranged in weight from and the shell) from Tridacna clams are known 6.8 kg (A) to 18.4 g (E) and in maximum length in the trade (e.g. Kunz and Stevenson, 1908; from approximately 27 to 2.6 cm. The large size Bari and Lam, 2010; Singbamroong et al., 2015; and weight of some of the samples precluded our see also www.pearl-guide.com/forum/content. normal pearl testing procedure, so we based our php?76), but due to their often rather dull whit- conclusions mostly on careful observation of sur- ish appearance and baroque shape (e.g. Figure face textures with the unaided eye and the mi- 2) they have not gained much interest so far, croscope (Eickhorst LED Leica Gemmaster). In except among a few pearl collectors. The shell addition, for sample E we performed Raman spec- material of Tridacna clams consists of regularly troscopy with a Renishaw InVia microscope and and densely interwoven aragonite fibres, similar chemical analysis by energy-dispersive X-ray fluo- to Strombus gigas (queen conch: Osuna-Mascaró rescence (EDXRF) spectroscopy using a Thermo et al., 2014) and many other gastropods. This partially results in fine ‘flame structures’ when viewed in reflected light (Hänni, 2010). As a con- Figure 2: A large hollow natural blister is shown attached to sequence, both natural pearls and polished shell the inside of a giant clam shell (Tridacna gigas). A loupe is shown for scale; the shell measures approximately 26 cm pieces from Tridacna clams often show such wide. Photo by Luc Phan, © SSEF. flame structures on their surface. However, not all non-nacreous white natural pearls claimed to be from Tridacna clams (Lai, 2014; Singbam- roong et al., 2015) necessarily originate from the Tridacninae subfamily. They may also be the beautiful products of other mollusc species— misnamed as Tridacna clam pearls, since there is currently no method for the species identifica- tion of such non-nacreous white pearls. This is very much in contrast to nacreous pearls, which currently can be separated genetically (Meyer et al., 2013), and also in some cases by UV- Vis-NIR reflectance and Raman spectroscopy.

Fake Pearls Made from Tridacna gigas Shells 425 Gemmological Brief

Scientific Quant’X instrument. Also, X-radiography was performed on the three smaller samples (C, D and E) using a Yxlon Cougar digital X-ray setup.

Visual and Microscopic Observations We divided the study specimens into two catego- ries according to their shape (again, see Figure 1). The largest sample (A) displayed a baroque shape, visually somewhat reminiscent of the wave-like form of Tridacna shell. The remaining specimens (B–E) were oval to slightly baroque, and thus were more typical of the shapes exhib- ited by pearls. Viewed with reflected light, all five specimens showed distinct curved, layered structures across their entire surfaces. These structures had no di- Figure 3: The surface of specimen B (8.6 cm long), cut and rect correlation to the shapes of the specimens, polished from Tridacna shell, exhibits distinct curved lines but were consistent with the undulating layered representing seasonal growth layers. Photo by V. Lanzafame, © SSEF. structures of Tridacna clam shell. Sample B ex- hibited a complex curved and folded structure (Figure 3) that appeared to represent the hinge of of manufactured shell material that have been pre- the clam; this area possesses the thickest accumu- viously examined at SSEF (e.g. Krzemnicki, 2006). lation of calcium carbonate in Tridacna shells. Using a strong transmitted fibre-optic light Close examination of all the samples further re- source, it was possible to investigate the internal vealed distinct polish marks in random orientations structure of the five study samples. All showed dis- (e.g. Figure 4), as would be expected from items tinct and sharply defined internal layering (Figure worked into a roundish shape. The low-quality 5), representing the seasonal calcium carbonate polish, suggesting a rushed ‘production’ of these precipitation layers of the shell in Tridacna spe- items, contrasts with the highly polished specimens cies. Such features are not commonly observed in pearls, which form by precipitation of concentric spherical layers within the pearl sac of a mollusc. Figure 4: Distinct polish marks on the surface of fake Although surface- or subsurface-related striae pearl sample C result in a low-quality polish. Photo by in genuine Tridacna pearls might occasionally M. S. Krzemnicki, © SSEF; image width 10 mm. produce a somewhat layered appearance with transmitted fibre-optic illumination (Lai, 2014),

Figure 5: Viewed with transmitted fibre-optic illumination, this close-up of specimen D (22.5 g) reveals the layered structure of the Tridacna shell from which it was cut. Photo by M. S. Krzemnicki, © SSEF; image width 11 mm.

426 The Journal of Gemmology, 35(5), 2017 Gemmological Brief

Figure 6: A reported ‘giant pearl’ weighing 34 kg provides a recent example of a fake pearl that made its way into worldwide headlines via the Associated Press in August 2016. The shape, layered structure and poor surface polish provide strong combined evidence that this object has been manufactured from Tridacna shell.

the present samples did not show any such Advanced Testing striae, but rather only a badly polished surface. Raman spectroscopy of sample E revealed that it The complex and sharp banding exhibited by consisted of aragonite, as expected for Tridacna the present samples (e.g. Figures 3 and 5) is also clams (Hänni, 2010). EDXRF analysis of this sam- very different from the weak circling bands oc- ple showed the expected major amounts of Ca casionally observed in non-nacreous white pearls along with traces of Sr (0.25 wt.% SrCO3), but from various molluscs, such as spp. with Mn below the detection limit, clearly sup- (Ho and Zhou, 2015) and Fusinus spp. (Bari and porting a formation of the biogenic calcium car- Lam, 2010, p. 75). These circles (seen as parallel bonate in marine waters. X-radiography of sam- bands when viewed from the side) are due to ples C, D and E revealed no discernible internal growth heterogeneities aligned by the rotation of structures such as layers or internal cavities in the pearl during its formation (Gueguen et al., any of these specimens. This result is very com- 2015). Typically these bands are rather broad and mon for non-nacreous pearls or shells (or beads diffuse, and are visible either as a sub-surface ef- made from such shells) that consist completely of fect when illuminated with a strong light source or densely interwoven aragonite fibres. at the surface (i.e. in nacreous pearls), where they may negatively affect the quality of a pearl. Such pearls commonly show a distinct rotational shape Further Cases of Fake Pearls from (button to long-prismatic oval) and occasionally Tridacna Clams reveal distinct flame structures radially emanating From time to time, the authors’ laboratory is from rotational axis points at their top and bottom. asked to analyse ‘giant pearls’, and these objects Viewed with the microscope, some of the are often accompanied by dubious identifica- five study samples revealed weak and fine tion and appraisal documents. Since the inter- flame structures perpendicular to the layering, national media highlighted such a ‘giant pearl’ similar to those described by Hänni (2010), but in August 2016 (e.g. Figure 6), the number of no flame structures were seen radially ema- such requests has increased steadily. Although nating from a distinct (rotational axis) point. the authors have not personally studied the ‘gi- Based on these observations, we concluded ant pearls’ claimed to originate from Tridacna that all five study specimens were fake pearls that clams that have recently appeared in the me- had been cut and polished from the massive shells dia, we are convinced that most—if not all—of of Tridacna clams. Such imitations—typically of them are in fact fakes that were manufactured rather small size—have been manufactured since from the shell of Tridacna clams. This opinion historic times (mostly then from Unio freshwater is based on their apparent similarity in shape, mussel shells) and have been described in detail by layered structure and surface polish to the study Kunz and Stevenson (1908, pp. 361, 494 and 497). samples we described above.

Fake Pearls Made from Tridacna gigas Shells 427 Gemmological Brief

Figure 8: This polished Tridacna shell bead (~23 × 16 mm or 63 ct) was dyed to imitate a Melo pearl. Note the well- developed flame structure, as would be expected for a Figure 7: This ‘pearl’ (18.6 mm in diameter) is actually a genuine Melo pearl. Photo by M. S. Krzemnicki, © SSEF. bead cut from Tridacna shell. The shell layers are distinctly visible when illuminated with fibre-optic lighting. Photo by M. S. Krzemnicki, © SSEF. sizes typical for gastropod pearls (e.g. Figure 7). They were polished with great care to display their fine flame structure and perfectly shaped to Still, the media hype about such ‘giant pearls’ fit into jewellery. As such, they have been mistak- is worth highlighting, as it reveals the context in enly bought as non-nacreous natural pearls, even which modern urban myths are presented to the by knowledgeable pearl dealers. Moreover, these general public. For those who have read about manufactured ‘pearls’ may be dyed orange to imi- several such ‘giant pearl’ discoveries, the themes tate Melo pearls (Wentzell, 2006; Sturman et al., sound very familiar. The stories include emotions 2011; Figure 8). Raman spectroscopy of one such such as greed and tragedy (a diver dies as he is Melo imitation showed no peaks at 1134 and 1527 trying to remove the ‘pearl’ from the giant clam cm−1 characteristic of the natural-colour pigment but is stuck in the closing shell), unexpected in Melo (and conch) pearls, but did reveal three discoveries but ignorance of their value (a poor broad features at 1519, 1499 and 1363 cm−1 that fisherman finds the ‘pearl’ and keeps it as a per- closely matched the broad Raman peaks of or- sonal item without knowing its ‘true’ value) and ganic dye (possibly red eosin; Krzemnicki, 2006). fairy-tale endings that involve achieving wealth and fortune and, hopefully, happiness (finally the ‘giant pearl’ is appraised by some unknown Conclusions source as being of enormous value—for example, Based on our observations and analyses, the five US$100 million—with an open ending as to how specimens submitted as ‘pearls’ reportedly origi- much money the poor fisherman will actually ob- nating from giant clams were identified unambig- tain). Although such stories may be entertaining uously as beads cut and polished from Tridacna and intriguing, the same themes have been used shell. The main criterion for the detection of all and repeated with great detail since historic times these fake pearls was the presence of distinctly (Kunz and Stevenson, 1908, p. 144), mostly to cre- discernible shell layers (sometimes overprinted ate illusion and interest in such exotic ‘oddities’. by fine flame structures). Unnoticed by the media, but occasionally en- Considering the similarity of these speci- countered in the laboratory and reported in the mens to numerous other items on the Internet gemmological literature, are smaller fake pearls or in pictures sent to us, we assume that most that most probably have been cut and polished of these others also are fakes, and as such have from Tridacna clams (Disner and Notari, 2015). essentially no commercial value. This is very In the past few years, SSEF has analysed a few much in contradiction to media reports or du- such specimens, cut into roundish shapes and bious appraisal documents, which unfortu-

428 The Journal of Gemmology, 35(5), 2017 Gemmological Brief

nately are too often reproduced and relinked Kunz G.F. and Stevenson C.H., 1908. The Book of the by reputed news sources without question. Pearl: The History, Art, Science, and Industry of It is also important to reiterate that Tridac- the Queen of Gems. The Century Co., New York, na clams are endangered species listed in Ap- New York, USA, 826 pp. Lai L.T.-A., 2014. Gem News International: A large pendix II of CITES (2016) and therefore are baroque Tridacna gigas (giant clam) pearl. Gems protected. Any international trade of shells or & Gemology, 50(3), 247. pearls from Tridacna requires an official per- Meyer J.B., Cartier L.E., Pinto-Figueroa E.A., mit before export. As such, trade organizations Krzemnicki M.S., Hänni H.A. and McDonald actively have banned the use of Tridacna shell B.A., 2013. DNA fingerprinting of pearls to beads in jewellery or as beads for pearl culti- determine their origins. PLoS ONE, 8(10), article vation in recent years (Zhou and Zhou, 2015). e75606, 11 pp., http://dx.doi.org/10.1371/journal. And, finally, this study reminds us of the in- pone.0075606. Osuna-Mascaró A., Cruz-Bustos T., Benhamada S., genuity of mankind to create illusion and gar- Guichard N., Marie B., Plasseraud L., Corneillat nish fraud with an appealing myth. The authors M., Alcaraz G., Checa A. and Marin F., 2014. hope that with this article, the chapter on the so- The shell organic matrix of the crossed lamellar called ‘giant pearls’ from Tridacna clams can be queen conch shell (Strombus gigas). Comparative closed, at least in the gemmological community. Biochemistry and Physiology Part B: Biochemistry and Molecular Biology, 168, 76–85, http://dx.doi. org/10.1016/j.cbpb.2013.11.009. References Rosewater J., 1965. The family Tridacnidae in the Bari H. and Lam D., 2010. Pearls. Skira Editore, Milan, Indo-Pacific. Indo-Pacific Mollusca, 1(6), 347– Italy, 336 pp. 394. CITES, 2016. Appendices I, II and III. Convention Sarasin F., 1904. Bericht über die Sammlung für on International Trade in Endangered Species Völkerkunde des Basler Museums für das Jahr of Wild Fauna and Flora, Geneva, Switzerland, 1903. Verhandlungen der Naturforschenden 46 pp., https://cites.org/sites/default/files/eng/ Gesellschaft in Basel, 15, 346–355. app/2016/E-Appendices-2016-11-21.pdf. Singbamroong S., Ahmed N., Ahmed A.R., Karam M., Dame R.F., 2011. Ecology of Marine Bivalves: An Hassan G., Mohammed S. and Muhairi N.A., 2015. Ecosystem Approach, 2nd edn. CRC Press, Boca Observations on natural non-nacreous pearls Raton, Florida, USA, 283 pp. reportedly from Tridacna (clam) species. 34th Disner E. and Notari F., 2015. Gem Notes: Gastropod International Gemmological Conference IGC, shell beads disguised in a . Journal Vilnius, Lithuania, 26–30 August, 125–127. of Gemmology, 34(7), 572–574. Sturman N., Lomthong P. and Homkrajae A., 2011. Figuier L., 1868. The Ocean World: Being a Descriptive An imitation “Melo pearl”. Gemological Institute History of the Sea and Its Living Inhabitants. of America, Bangkok, Thailand, 21 January, 7 pp., Chapman & Hall, London, 605 pp., http://dx.doi. www.giathai.net/pdf/An_Imitation_Melo.pdf. org/10.5962/bhl.title.99574. Wentzell C.Y., 2006. Lab Notes: Imitation Melo Gueguen Y., Czorlich Y., Mastail M., Le Tohic B., “pearls”. Gems & Gemology, 42(2), 166–167. Defay D., Lyonnard P., Marigliano D., Gauthier Zhou J.Y. and Zhou C., 2015. Lab Notes: Conservation J-P., Bari H., Lo C., Chabrier S. and Le Moullac G., concerns over use of Tridacna shell in imitation 2015. Yes, it turns: Experimental evidence of pearl pearls. Gems & Gemology, 51(1), 62–63. rotation during its formation. Royal Society Open Science, 2, article 150144, 8 pp., http://dx.doi. org/10.1098/rsos.150144. Hänni H.A., 2010. Explaining the flame structure of non-nacreous pearls. Australian Gemmologist, The Authors 24(4), 85–88. Dr Michael S. Krzemnicki FGA and Ho J.W. and Zhou C., 2014. Lab Notes: Natural pearls Dr Laurent E. Cartier FGA reportedly from a Spondylus species (“thorny” oyster). Gems & Gemology, 50(3), 241–242. Swiss Gemmological Institute SSEF Krzemnicki M.S., 2006. A worked shell bead as an Aeschengraben 26, 4051 Basel, Switzerland imitation of a Melo pearl. SSEF Alumni Newsletter, Email: [email protected] No. 5, 5–7.

Fake Pearls Made from Tridacna gigas Shells 429 Gemmological Brief

Large 12-Rayed Black Star Sapphire from Sri Lanka with Asterism Caused by Ilmenite Inclusions

Thanh Nhan Bui, Pascal Entremont and Jean-Pierre Gauthier

A large (112.64 ct) black star sapphire of probable Sri Lankan origin that exhibits 12-rayed asterism was studied for this report. As in other 12-rayed star sapphires, its phenomenal appearance is due to the presence of ori- ented needle-like inclusions that produce two superimposed six-rayed stars that are rotated 30° relative to one another. However, Raman spectroscopy combined with optical microscopy unexpectedly revealed that the inclusions responsible for both stars consist of the same mineral, ilmenite. By contrast, 12-rayed star sapphires from Thailand typically contain separate inclusion sets of rutile and -ilmenite series minerals corresponding to the two six-rayed stars.

The Journal of Gemmology, 35(5), 2017, pp. 430–435, http://dx.doi.org/10.15506/JoG.2017.35.5.430 © 2017 The Gemmological Association of Great Britain

Introduction In the gemmological literature, there is a lack Asterism is an optical phenomenon that occurs of systematic identification of minerals - in gemstones containing oriented needle-shaped ing to asterism in corundum and, more gener- inclusions. In corundum, due to the three-fold ro- ally, in asteriated gemstones. In this article, we tational symmetry of the basal pinacoid, networks use Raman spectroscopy to analyse both net- of needles are oriented in three different crystallo- works of needle inclusions in a large 12-rayed graphic directions that intersect at 120°. As a con- black star sapphire reportedly from Sri Lanka, sequence, typical asterism in corundum consists as well as in smaller samples from the same of a six-rayed star composed of three intersecting source and from Thailand for comparison. branches. The exsolved acicular inclusions, with the same rotational symmetry, may be oriented Materials and Methods along two different hexagonal prisms of the host The large star sapphire (Figure 1) weighs 112.64 crystal. As a general rule, rutile needles are orient- ct and was purchased in Colombo, Sri Lanka, by ed parallel to the growth zoning and the second- author PE in approximately 1985. No information order hexagonal prism of the host corundum, concerning the exact origin of the stone was avail- while needles of hematite-ilmenite series miner- able. Named ‘Ceylon Stars’, it is the largest 12-rayed als are oriented perpendicular to these features star sapphire from Sri Lanka that is known to the (Hughes, 1997, p. 94). When both orientations of authors. It resembles another large 12-rayed star acicular inclusions are present in the same corun- sapphire (70.79 ct), also from Sri Lanka, that is very dum host, they result in a 12-rayed star. dark blue and mounted in a ring in the National

430 The Journal of Gemmology, 35(5), 2017 Gemmological Brief

a b

Figure 1: The 112.64 ct ‘Ceylon Stars’ sapphire, from the collection of P. Entremont, displays 12-rayed asterism, as shown here with pinpoint illumination positioned (a) over its centre and (b) obliquely. Photos by P. Entremont.

Gem Collection of the Smithsonian National Mu- Results and Discussion seum of Natural History (http://geogallery.si.edu/ index.php/10002721). Large Sri Lankan Black Star Sapphire For comparison, five other 12-rayed star sap- When illuminating the cabochon at its centre (Fig- ure 1a) or obliquely (Figure 1b) with pinpoint il- phires from Sri Lanka (Figure 2A–E)—all weighing lumination, we readily observed the 12-rayed star. less than 5 ct and obtained by author PE at the Growth zoning was seen as bands along three same time as the 112.64 ct stone—also were exam- crystallographic directions in the basal plane of ined, as well as a 12-rayed star sapphire from Thai- the pinacoid of the corundum host. The hexagonal land (Figure 2F) weighing 8.05 ct that was recently growth bands were off-centre relative to the dome obtained by author TNB in Chanthaburi, Thailand. of the cabochon. This is probably due to weight All samples were observed with a binocular optimisation during cutting, as supported by the microscope in reflected light at magnifications of backside of the cabochon being kept in its rough 15×–1,000× to examine their acicular inclusions. state. The body colour of the sapphire was diffi- The inclusions in all samples were then identified cult to discern due to the dense concentration of using a Horiba LabRAM 800HR micro-Raman spec- acicular inclusions. Nevertheless, strong transmit- trometer. Calibration was performed on a ted illumination revealed that its body colour was −1 substrate (first-order Raman peak of 520.7 cm ). A mainly dark blue with some areas showing a more green laser (514 nm) was used to excite the sam- violet hue. ples, and the power (6.6 mW) was modulated at The 12-rayed star was composed of two six- 50% and 100%. The acquisition time for each spec- rayed stars rotated 30° relative to one another. trum ranged from 1 to 2 minutes, and each spec- This seems consistent with the usual exsolution tral acquisition was performed twice. Due to the of inclusions in this type of corundum, in which very small size of the inclusions (a few micrometres one set of needles (perpendicular to the growth wide), we used an optical magnification of 1,000×. bands in the corundum) consists of hematite- In order to plot several curves in the same graph, ilmenite minerals, and the other set (parallel to the spectra were normalized according to the most the growth bands) consists of rutile (cf. Bui et intense Raman peak. The background was not sub- al., 2016). These latter inclusions typically appear tracted from the spectra. white and are thinner in dimension, producing

Large Black Star Sapphire 431 Gemmological Brief

A B C

D E F

Figure 2: Several additional 12-rayed star sapphires were studied for comparison, including five others from Sri Lanka (A–E; 1.53–4.19 ct) and one from Thailand (F; 8.05 ct). The Sri Lankan samples range from purple to violet, except one that can be considered black (D). The Thai stone (F) is also a black star sapphire. In samples A–D, all rays of the stars are brownish, while samples E and F have both brownish and whitish rays corresponding to differences in the inclusions responsible for their stars. Photos by T. N. Bui (A–E) and J.-P. Gauthier (F). sharp asterism, whereas the former are darker ure 3a), or parallel and oblique at 60° (e.g. Figure and wider, giving broader rays. However, in the 3b). From these relative orientations of the acicular present stone, the needles of the two stars were inclusions compared to the growth bands, we ex- similar in colour. For this reason, we decided to pected to attribute the inclusions in Figure 3a to examine this 12-rayed sapphire more carefully to the hematite-ilmenite series and those in Figure determine the exact nature of its inclusions. 3b to rutile. However, the density and the width Close inspection by optical microscopy at high of inclusions varied in different areas of the stone. magnification near the surface of the cabochon Also, the average width of the inclusions oriented revealed some details about the microstructure perpendicular to the growth bands of the host co- of the growth bands. Networks of oriented need- rundum was narrower than the inclusions oriented les and platelets—in three different orientations parallel to the growth bands. This explains the dif- intersecting at 60°/120°, typical of the three-fold ference in sharpness between the two six-rayed rotational symmetry of corundum—were present stars constituting the 12-rayed asterism. within the basal plane. Compared to the growth Figure 4a illustrates a dark-coloured region bands, most of the acicular inclusions were ori- that was depleted of acicular inclusions. Instead, ented perpendicular and oblique at 30° (e.g. Fig- it contained a lower density of somewhat larger

432 The Journal of Gemmology, 35(5), 2017 Gemmological Brief

a b

Figure 3: Two networks of needles constitute the growth zoning in the large 12-rayed sapphire, oriented perpendicular (a) and parallel (b) to the growth bands in the host corundum. The corundum growth bands are horizontal in both of these images. Photomicrographs by T. N. Bui in brightfield illumination; field of view 400 × 300 μm. black inclusions. High magnification revealed their acicular inclusions, as well as the black inclusions, plate-like shape (Figure 4b), with edges parallel or were identified as ilmenite (FeTiO3); no hematite or perpendicular to the acicular inclusions. Their ap- rutile inclusions were found. Typical Raman spectra pearance was similar to the magnetite inclusions for the ilmenite inclusions were characterized by found in ‘Gold Sheen’ sapphires (see Figure 13 a strong band at 678 cm−1, as depicted in Figure 5 in Bui et al., 2015). In the present case, however, (spectra b–d). The other vibration modes for ilmen- these black inclusions were isolated from the net- ite were 162, 194, 221, 256, 291, 329, 374, 451 and works of acicular inclusions. 597 cm−1. The obtained spectra are in good agree- In agreement with previous studies (e.g. Palanza ment with natural ilmenite (e.g. Rull et al., 2004, et al., 2008; Bui et al., 2015), Raman spectra of the 2007; Bui et al., 2015) and pure synthesized ilmen- inclusions consisted of superimposed signals from ite (e.g. Sharma et al., 2009; Guan et al., 2013). both the host sapphire and the tiny inclusions. Fig- ure 5a illustrates the spectrum of sapphire (α-Al2O3 Thai Black Star Sapphires corundum), including peaks at 379, 418, 430, 449, Black star sapphires, including those displaying 576 and 750 cm−1. Surprisingly, both networks of 12 rays, are usually attributed to the Ban Kha Cha

Figure 4: Near the surface of the large sapphire is an area that is free of inclusions that contribute to the asterism; this area appears dark and contains black inclusions (a: field of view 3.25 × 2.60 mm). A closer view of the black inclusions reveals their plate-like shape with edges that are parallel or perpendicular to the acicular inclusions (b: field of view 400 × 300 μm). Photomicrographs by T. N. Bui in brightfield illumination.

a b

Large Black Star Sapphire 433 Gemmological Brief

Raman spectra of Fe/Ti-rich from acicular Raman Spectra inclusions in black star sapphires, and therefore no identification of their exact mineralogy. Figure 5 demonstrates the difference between e. Fe/Ti-oxide a typical Raman spectrum of Fe/Ti-rich oxide in- clusions in our 12-rayed black star sapphire from

678 Thailand (Figure 2F) and those found in the large 194 256 291 451 597 Sri Lankan gem (Figure 1). Further characterization 162 221 329 374 d. Ilmenite of the mineralogical nature of the Fe/Ti-rich oxide acicular inclusions in the Thai sample is beyond the scope of the present study. We also confirmed the presence of rutile inclusions in this stone by c. Ilmenite Raman spectroscopy (not plotted in Figure 5). Intensity Our 12-rayed black star sapphire from Thailand (Figure 2F) had the same appearance as the one reported by Schmetzer and Glas (2001). While one b. Ilmenite six-rayed star was brownish, the other was whitish, 418 which was not the case for the large Sri Lankan sample in this study. Moreover, the branches of the 430 750 whitish star in 12-rayed black star sapphires from 379 449 576 a. Sapphire Thailand were sharper than those of the brownish 200 400 600 800 1000 star, due to the narrower width of the rutile nee- Raman shift (cm−1) dles. In the large Sri Lankan sample, the six-rayed star parallel to the growth zoning was sharper than Figure 5: For the large sapphire, Raman spectra are shown for the host corundum (a); the inclusions responsible for the the other rays seen in this stone. The fact that it 12-rayed star, identified as ilmenite, present as narrow (b) and contains only ilmenite inclusions is consistent with thick (c) needles and/or platelets; and for black inclusions of its Sri Lankan origin, which is distinctive from the ilmenite that are not related to the asterism (d). The ilmenite inclusion assemblage found in Thai stones. spectra are distinct from those of Fe/Ti-rich oxide acicular inclusions in black star sapphires from Thailand (e). The Sri Lankan Star Sapphires vertical dashed lines indicate the Raman peaks of corundum The smaller 12-rayed star sapphires that were superimposed on those of the analysed inclusions. studied for comparison had body colours rang- ing from purple to violet (Figures 2A–C and 2E) and black (Figure 2D). In each sample, the acicu- mine in Thailand, based on their physical and lar inclusions parallel to the first-order hexago- chemical characteristics. The acicular inclusions nal prism were identified by Raman spectroscopy forming the classic six-rayed black star sapphires as ilmenite. Ilmenite also constituted the second have been reported as an exsolution of hema- set of acicular inclusions—as for the 112.64 ct tite (Weibel and Wessicken, 1981) or both he- stone—except for one sample (Figure 2E), in matite and ilmenite (Gübelin and Koivula, 2008, which the second network consisted exclusively p. 214). It was later demonstrated by scanning of rutile needles, which was consistent with the electron microscopy with energy-dispersive X- whitish colour of its corresponding six-rayed star. ray spectroscopy (Moon and Phillips, 1984) and Twelve-rayed stars are quite rare among Sri by electron microprobe analysis (Saminpanya, Lankan sapphires (Hughes, 1997, p. 406). By ana- 2001) that the inclusion exsolution is of the same lysing the pattern of the growth zoning (formed by chemical composition (Fe/Ti-rich oxides) but exsolved inclusions of epigenetic ilmenite) in our not pure hematite or pure ilmenite. In 12-rayed samples, we can deduce a relatively constant input star sapphires from Thailand, the additional net- of fluids rich in Ti and Fe during crystal growth. work of needles—parallel to the second hexago- The lack of notable variation in fluid composition nal prism of the corundum host and producing was suitable for ilmenite growth along both the the second six-rayed star at 30° with respect to first- and second-order hexagonal prisms in all but the first one—is typically attributed only to rutile one of our samples. Microscopic observation of (Schmetzer and Glas, 2001). To our knowledge, all the Sri Lankan samples demonstrated that the there are no reports in the literature containing width of acicular ilmenite inclusions was narrower

434 The Journal of Gemmology, 35(5), 2017 Gemmological Brief

for those oriented perpendicular to the growth Bui T.N., Deliousi K., De Corte K. and Gauthier J.-P., bands in the corundum. This explains the sharp- 2016. Gem Notes: Star sapphire showing a vari- ness difference between the two six-rayed stars able number of rays. Journal of Gemmology, 35(3), 197–199. constituting the 12-rayed asterism. In addition, the Guan X., Zheng J., Zhao M., Li L. and Li G., 2013. presence of the same mineral—ilmenite—causing Synthesis of FeTiO3 nanosheets with {0001} facets both six-rayed stars in all but one Sri Lankan sam- exposed: Enhanced electrochemical performance ple is consistent with the uniform brownish colour and catalytic activity. RSC Advances, 3(33), 13635– observed in all 12 rays of those samples (Figures 1 13641, http://dx.doi.org/10.1039/c3ra22125c. and 2A–D). However, both a brownish and whit- Gübelin E.J. and Koivula J.I., 2008. Photoatlas of In- clusions in Gemstones, Vol. 3. Opinio Publishers, ish appearance of the rays may be shown by some Basel, Switzerland, 672 pp. Sri Lankan 12-rayed star sapphires (see Figure 2E Hughes R.W., 1997. Ruby & Sapphire. RWH Publish- and http://geogallery.si.edu/index.php/10002721/ ing, Boulder, , USA, 511 pp. corundum-var-star-sapphire) and also in 12-rayed Moon A.R. and Phillips M.R., 1984. An electron black star sapphires from Thailand (Schmetzer microscopy study of exsolved phases in natural black Australian sapphire. Micron and Microscopica Acta, and Glas, 2001; Figure 2F), which contain inclu- 15(3), 143–146, http://dx.doi.org/10.1016/0739-6260 sion networks of both the hematite-ilmenite series (84)90044-3. and rutile. Palanza V., Di Martino D., Paleari A., Spinolo G. and Prosperi L., 2008. Micro-Raman spectroscopy ap- plied to the study of inclusions within sapphire. Conclusion Journal of Raman Spectroscopy, 39(8), 1007–1011, The presence of a single mineral—ilmenite—as http://dx.doi.org/10.1002/jrs.1939. the cause of 12-rayed asterism in sapphire was Rull F., Martinez-Frias J., Sansano A., Medina J. and Edwards H.G.M., 2004. Comparative micro-Raman documented here for the first time in the largest study of the Nakhla and Vaca Muerta meteorites. such gem known to the authors, a 112.64 ct black Journal of Raman Spectroscopy, 35(6), 497–503, star sapphire of probable Sri Lankan origin. For http://dx.doi.org/10.1002/jrs.1177. comparison, we examined five smaller star sap- Rull F., Martinez-Frias J. and Rodríguez-Losada J.A., phires from Sri Lanka and one star sapphire from 2007. Micro-Raman spectroscopic study of El Gasco pumice, western Spain. Journal of Raman Thailand, all of which displayed 12-rayed aster- Spectroscopy, 38(2), 239–244, http://dx.doi.org/ ism. Visual observation and optical microscopy 10.1002/jrs.1628. showed a similar appearance for both networks of Saminpanya S., 2001. Ti-Fe mineral inclusions in star inclusions (i.e. both perpendicular and parallel to sapphires from Thailand. Australian Gemmologist, the growth bands of the host corundum). Raman 21, 125–128. spectroscopy confirmed that both sets of inclusion Schmetzer K. and Glas M., 2001. Zwölfstrahliger Stern- saphir aus Bang-kha-cha, Thailand. Lapis, 11, 40– networks in all but one of the Sri Lankan sapphires 42. consisted of ilmenite, which caused both six-rayed Sharma Y.K., Kharkwal M., Uma S. and Nagarajan R., stars that constitute the 12-rayed asterism. By con- 2009. Synthesis and characterization of titanates trast, the 12-rayed asterism in Thai star sapphires of the formula MTiO3 (M=Mn, Fe, Co, Ni and is attributed to separate networks of hematite-il- Cd) by co-precipitation of mixed metal oxalates. Polyhedron, 28(3), 579–585, http://dx.doi.org/10. menite minerals and rutile. In addition, separate 1016/j.poly.2008.11.056. networks of ilmenite and rutile were confirmed in Weibel M. and Wessicken R., 1981. Haemetit als one of our Sri Lankan samples. Einschluss im schwarzen Sternsaphir. Gemmologie: The identity of the mineral(s) causing the aster- Zeitschrift der Deutschen Gemmologischen Gesell- ism in 12-rayed star sapphires can be inferred from schaft, 30(3/4), 170–176. the colour of the branches of each six-rayed star: ilmenite corresponds to brownish rays, and rutile produces whitish rays. The sharpness of the rays The Authors correlates to the width of the inclusions, regardless Thanh Nhan Bui of the identity of the mineral that causes them. IMCN/NAPS, Université catholique de Louvain, Louvain-la-Neuve, Belgium References Email: [email protected] Bui T.N., Deliousi K., Malik T.K. and De Corte K., 2015. Pascal Entremont and Jean-Pierre Gauthier From exsolution to ‘Gold Sheen’: A new variety of Centre de Recherches Gemmologiques, corundum. Journal of Gemmology, 34(8), 678–691, Nantes, France http://dx.doi.org/10.15506/JoG.2015.34.8.678.

Large Black Star Sapphire 435 Excursions

GIT 2016 Pre-Conference Field Trip to Mogok, Myanmar November 2016

Tasnara Sripoonjan, Saengthip Saengbuangamlam and Thanong Leelawatanasuk

The Gem and Jewelry Institute nis Alexandris (Germany), Arent production. Other attractions of Thailand (GIT) organized a and Helene Heilmann (Green- included visits to educational field trip to Mogok, Myanmar, to land), Mary Ng (Hong Kong), facilities, gem markets and sev- accompany the 5th GIT Interna- Meenu Brijesh Vyas (India), Ken- eral historical pagoda sites. tional Gem and Jewelry Confer- taro Emori (Japan), Yoko Okubo ence, which was held 14–15 No- (Japan), William Wold (Nether- En Route to Mogok: The vember 2016 (see report on pp. lands), Sang Phil Oh (South Ko- group flew from Bangkok to 445–447 of this issue). This 9–13 rea), Young Soo Chung (South Mandalay and then boarded November pre-conference excur- Korea), Yuanchan Chaiyawat a van. Our first stop was the sion was attended by 15 overseas (Thailand), Chen Shen (USA) Werawsana Jade Pagoda near participants from various fields and Cynthia Unninayar (USA). Amarapura Township, about related to gems and jewellery (i.e. The group was led by Aung Na- 20 km from the airport. The gemmologist, mineralogist, jour- ing Thun, a representative of the pagoda is decorated with sev- nalist, gem retailer, gem whole- Myanmar Gem and Jewellery eral varieties of jade, saler, gem collector and retail Entrepreneurs Association, as including ‘ice’, green and lav- jeweller): Marcelo E. Souza (Bra- well as three GIT gemmologists ender types. We then visited a zil), Dr Geng Li (China), Ioan- (the authors). gemmological laboratory and The goal of the five-day trip school in Mandalay, where we was to examine gem deposits, stayed overnight before pro- Editor’s note: This report gives a de- active mining operations and ceeding to Mogok early the scription of the Mogok area just before stone trading in Mogok. Partici- next morning. it was closed to foreigners by Myan- pants had many opportunities Our route followed the Mand- mar’s government in December 2016. For two previous Excursions reports on to learn about the geology, min- alay–Myitkyina highway, passing Mogok, see The Journal, 34(1), 2014, ing and recovery techniques, through an immigration check- 55–67. as well as ruby and sapphire point near Pyin Oo Lwin in the

A panoramic view of ‘Ruby Land’ greets visitors to the Mogok valley. Photo by T. Sripoonjan.

436 The Journal of Gemmology, 35(5), 2017 Excursions

Shan Highland, some 67 km east cred gilded Buddhas. The Bud- in Shansu Quarter. Like Phaung of Mandalay. The trip to Mogok dhas are brought out for worship Daw Oo, this temple contains took around six hours on good and placed on gem-studded, white marble Buddhas, along pavement alternating with dirt gold-and-silver plinths for one with cabinets displaying innu- road, often quite winding. Upon day each year. The plinths are merable gemstones donated our arrival, we checked into the decorated with various gem- by local people. The gems and King Bridge Hotel and then vis- stones, including ruby, sap- jewellery on display there are ited a viewpoint on the main phire, jadeite and others. The a sign of the cultural affluence road to the east of the gem min- stones were mainly donated by and respect for the Buddha by ing region. It provided a pano- gem dealers and local people, the Burmese people. ramic vista of the Mogok Valley notably a former governor, and The Daw Nan Kyi temple with numerous villages flanked kept as one of the secret treas- is located in a spectacular set- by forested mountains. ures of Mogok. Our group was ting at around 1,520 m (5,000 fortunate to see these plinths, ft) elevation, above the west- Mogok Monasteries: We vis- which are rarely displayed for ern side of Mogok. From there, ited three pagodas in the Mogok visitors. we could see the town of Kyat area. At the Phaung Daw Oo Chan Thar Gyi is another fa- Pyin and surrounding hillsides temple, a white marble Buddha mous temple in Mogok. It is sit- comprising the Mogok Stone is flanked on both sides by sa- uated on the hill of Minn Phaya Tract.

EN ROUTE TO MOGOK (A) The beautiful Werawsana Jade Pagoda near Amarapura is decorated with jadeite of various colours. (B) Thousands of tons of jadeite slabs are cemented to the surface of the pagoda. (C) U Tommy Thein (left) introduces his gemmological school in Mandalay. Photos by T. Sripoonjan (A–B) and S. Saengbuangamlam (C).

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MONASTERIES IN MOGOK (A) The former governor of Mogok and his son showed us treasures of the Phaung Daw Oo temple. (B) Chan Thar Gyi temple contains a collection of valuable gemstones and antique jewellery. (C) The Daw Nan Kyi Monastery affords an excellent view of the Mogok Stone Tract. Photos by T. Sripoonjan.

Bernardmyo Peridot Depos- and sanatorium established after marble, often with weathered its: Fine peridot is mined from the Third Anglo-Burmese War. A gneiss, and is locally intruded the Pyaunggaung area near Ber- cemetery there dates back more by syenite or veins. nardmyo, located in the north- than 120 years, based on the The mine is operated with heavy west part of Mogok. The deposits years 1888–1898 that were in- machinery, and excavators ini- in this area are well-known for scribed on headstones of British tially remove up to 20 m of over- producing peridot from veinlets soldiers. burden to reach secondary de- and pockets within a fine-grained posits containing the sapphires. peridotite rock. Although many Baw Mar Sapphire Mine: Lo- The miners use water cannons of the mines are run by the gov- cated northwest of Kyat Pyin to wash the gravels from the pit, ernment, we visited a private Township, about 18 km west of and the material is then routed operation owned by Purify Co. Mogok, is a well-known blue to a washing plant. The authors climbed down a sapphire mine called Baw Mar. We had an opportunity to shaft on traditional wooden We accessed the site in four- discuss the mine operation with ladders, where we saw active wheel-drive pickup trucks pro- the owners at their home. Our drilling using pneumatic ham- vided by the mine owners. The hosts gave us a warm welcome mers. There also was a small shaft geology of the area is complex, and took our group to view the used to transport equipment consisting mainly of regionally gem-sorting process. The mine and mined material. Near this metamorphosed rocks, especial- recently has produced blue peridot mine is a military station ly calc-silicates and graphitic sapphire in relatively large siz-

438 The Journal of Gemmology, 35(5), 2017 A B

C D E

PYAUNGGAUNG PERIDOT MINING AREA (A) The entrance of the Purify Company’s peridot mine is located in the mountains of the Bernardmyo area. (B–C) The Purify mine is accessed by a traditional wooden ladder, and a rope is attached to a winch for transporting mining equipment. (D) This view shows the typical underground workings in the Purify peridot mine. (E) Graves of British soldiers from the late 19th century are located near the peridot mines. Photos by T. Sripoonjan.

BAW MAR MINE (A) The large open pit at Baw Mar is mined for blue sapphire. (B) Miners use water cannons to mobilize gravels in the pit. (C) Sorting of rough blue sapphires is done on-site. (D) U Ye Min Tun (left), one of the owners of the Baw Mar mine, displays some rough and faceted blue sapphires. Photos by T. Sripoonjan (A–B) and S. Saengbuangamlam (C–D).

A

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es (up to 3+ cm in diameter) in passes into jaw crushers, and the 2012, yielding approximately low-to-moderate qualities. Fine fragments are washed into jigs us- 450,000 carats. By comparison, gem-quality sapphire is occa- ing water jets. The jigs are hand- in 2016 the mine produced sionally found, and additional picked for ruby, spinel and other around 100,000 carats of ruby. At production consists of spinel of gems, and the rejected material the time we visited, mining took various colours. is further sorted by workers with place almost 400 m below the metal blades before it is trans- surface in a complex network Yadana Shin Ruby Mine: ported to the tailings pile outside of tunnels following the ruby- One of the most famous ruby the mine, where local people are bearing marble layers. How- mines of Mogok, Yadana Shin, allowed to go through it. Most of ever, most of the ruby-rich lay- is located approximately 4 km the mine’s ruby production is not ers were found at around 90 m north-west of the town of Mogok. of high quality, but only a few depth. The mine manager used Yadana Shin is a relatively mod- good stones are needed to make a scale model of the workings to ern operation that is exploited the operation viable. explain the sophisticated opera- underground as well as in open tion. The manager also took us pits. Miners access the under- Ruby Dragon Mine: This mine to visit the mine entrance, but ground workings using a series is located near Yadana Shin in unfortunately visitors were pro- of ladders. Ruby mineralization the Bawpadan area. Operated hibited from entering. The gem is hosted by fine-grained marble by Ruby Dragon Jade and Gems material (faceted pieces averag- with some brown mica. The ruby- in a joint venture with the My- ing 2–3 ct; exceptionally up to 10 bearing marble pieces are placed anmar government, this is one ct) is sorted on-site into various in secure bags and transported of the largest ruby mines in the qualities, and the least transpar- to the surface using a cable pul- Mogok area. The best overall ent stones are reportedly heated ley system. All the material then ruby production occurred in to improve their clarity.

YADANA SHIN MINE (A) Yadana Shin is one of the most well-known ruby mines in Mogok. (B) The mine workings are accessed by shafts, (C) which contain wooden ladders and timbering. (D) The mined material is passed through jaw crushers and then into jigs. (E) Workers sort the crushed rock by hand to recover the rubies. Photos by S. Saengbuangamlam (A, C) and T. Sripoonjan (B, D–E).

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440 The Journal of Gemmology, 35(5), 2017 A

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RUBY DRAGON MINE (A) The Ruby Dragon mine is surrounded by steep, forested slopes. (B) An elevator is used to access this Ruby Dragon shaft. (C) The mine manager shows a scale model of the underground workings. (D) The air in the shaft is hazy from the mining activities below. (E) Ore carts are used to bring the mined material to the surface. Photos by T. Sripoonjan (A–D) and S. Saengbuangamlam (E).

Excursions 441

A B

C D

MOGOK GEM MARKETS E F (A) Many kinds of rough samples, faceted stones and some jewellery are offered at the Cinema Lane mark- et. (B) This old cinema gives the gem market its name. (C) Gem traders en- thusiastically offer their stones to pro- spective buyers. (D) A strong torch is an indispensable tool for gem trading. (E–F) Faceted rubies and were available during our visit to Mogok. (G) The gem-trading atmosphere is busy at the so-called blue umbrella market. Photos by T. Sripoonjan.

G

442 The Journal of Gemmology, 35(5), 2017

Excursions

Our international group of participants gathered together at the Mogok Valley viewpoint. Photo courtesy of T. Sripoonjan.

Gem Markets in Mogok: There ple of Indian, Chinese and other Conclusions: The gem town of are two notable gem markets in ethnic backgrounds, along with Mogok has retained its charm as the town of Mogok, as well as some Thais. The buyers sit at ta- one of the most desirable plac- several smaller markets scattered bles under numerous blue um- es for gem enthusiasts to visit. throughout the Mogok area. At brellas and are offered gems by There are several active mining these open-air markets, mostly local dealers or brokers. We saw operations in the area, mainly for low- to medium-quality rough energetic dealers buying and ruby and sapphire, and mecha- and cut rubies, sapphires and selling gemstones enthusiastical- nized techniques are commonly other gems are traded among ly. Interestingly, we encountered used. However, the production the locals. The Yoke Shin Yone some of the same dealers that of fine-quality ruby and sapphire gem market (also known as the we saw at the morning gem mar- is scarce. We hope that Mogok ‘crystal market’, or Cinema Lane ket, offering us the same stones. will once again be open to visits since it is located within sight of The sellers especially focused on by foreigners in the future. the old cinema) operates daily foreigners once anyone showed in the morning. It occupies both interest in buying, and negotiat- sides of the street for about 100 ing the prices was a long, pains- Acknowledgements m. Some of the minerals and taking process. We saw various The authors thank GIT’s direc- rough gem parcels there were qualities of ruby, sapphire, spinel tor, Dr Pornsawat Wathanakul, reasonably priced. Also present and peridot, particularly as rough for her advice. Thanks also to were ornamental rocks and less- stones. Nevertheless, the prices academic advisors Dr Visut Pisu- common specimens, including seemed relatively high. We were tha-Arnond and Wilawan Atichat shells and fossils. A small amount not offered any obvious synthet- for their valuable comments and of imitations and synthetics was ics or imitations in this market. kind review of this article. noted at this market. We then visited the Panchan (or ‘blue umbrella’) gem mar- Tasnara Sripoonjan and Saengthip Saengbuangamlam are ket, the largest in Mogok, which gemmologists, and Thanong Leelawatanasuk is chief of the opens from 1:00 pm to around Gems Testing Department, at GIT in Bangkok, Thailand. 4:00 pm. In addition to Burmese Email: [email protected] traders, it is frequented by peo-

Excursions 443 Conferences

AGA Tucson Conference The 2017 Accredited Gemologists Association Confer- purportedly looked though them to find the location of ence in Tucson, Arizona, USA, took place 1 February, the sun through the fog that commonly blanketed the with the theme ‘Cutting Edge Gemology to Keep You cold seas in the Scandinavian region. in the Loupe’. Attended by 125 people, the event was Warren Boyd (R.T. Boyd Ltd, Oakville, Ontario, moderated by AGA president Stuart Robertson and fea- Canada) profiled two gem materials from the west- tured eight presentations. ern USA: Montana sapphires and ‘Apache Blue stone’ Christopher Smith (American Gemological Labo- from Arizona. A mechanized mining operation by ratories Inc., New York, New York, USA) reviewed vari- Potentate Mining LLC at the West Fork of Rock Creek ous systems for communicating colour in gemmology in Montana is producing sapphires in a variety of (i.e. Gem Dialogue, Color Scan, Color Master, GemSet, hues, and most are heat-treated to improve their co- Gemewizard and World of Color), and then introduced lour and clarity. Apache Blue stone has a turquoise- his ColorCodex Color Referencing System (Figure 1). like appearance and was recovered recently in coop- Consisting of a set of colour-range cards, each with six eration with a copper-mining company at a deposit textured foils for a specific hue that range from lighter located <1 km from the Sleeping Beauty turquoise to darker and more saturated, the ColorCodex provides deposit near San Carlos, Arizona. It appears to be pri- an intuitive, observer-based system for referencing (not marily composed of , along with multiple grading) colour in loose or mounted gems. minerals that formed through supergene processes; Elise A. Skalwold (Cornell University, Ithaca, New most of the material is stabilized before cutting by York, USA) gave two presentations. Her first one reviewed impregnating it with resin. her work, together with Dr William Bassett (retired pro- Yianni Melas (Limassol, Cyprus) described ‘Aqua- fessor of geology, Department of Earth and Atmospheric prase’, a relatively new bluish green from Sciences, Cornell University), on various mineralogical Africa. The rough material is hand-mined from an open and gemmological projects involving mineral physics. pit, and approximately 80% is processed locally. Chemi- Perhaps most intriguing was an investigation to identify cal analysis has revealed traces of various chromophoric a blue inclusion in a macle-twinned diamond that turned elements in Aquaprase, including Cr, Ni and Cu. out to be olivine; the reason for its anomalous colour is Gary Roskin (International Colored Gemstone As- still unknown. Skalwold’s second presentation examined sociation [ICA], New York, New York) provided some the possible use of iolite or as navigation aids by interesting background information on ICA, and then Viking seafarers. Referred to as ‘’, the Vikings noted various trends in coloured stones that he had

Figure 1: Christopher Smith discusses the fundamentals of colour space before introducing his ColorCodex Color Referencing System. Photo by B. M. Laurs.

444 The Journal of Gemmology, 35(5), 2017 Conferences

seen during the previous few days at the 2017 Tucson research on this famous gem. Although it shows no gem shows. Among the items he mentioned were irra- fluorescence to UV radiation, it displays long-lasting in- diated and heated morganite showing brownish pink to tense orange phosphorescence (for approximately one orangey pink coloration that was available in relatively minute). Recent analysis of the diamond with time-of- large sizes (10–40 ct), blue sapphires from a new de- flight laser ablation inductively coupled plasma mass posit in Madagascar (see pp. 391–392 of this issue for spectrometry showed that it contains an average of more on this material) and an abundance of Cu-bearing only 0.5 ppm boron, which is enough to produce its tourmaline from that showed good colour deep blue colour. saturation but was fairly included. The conference ended with the announcement of a Art Samuels (EstateBuyers.com and Vivid Dia- new Hanneman Award for contributions to the literature monds & Jewelry, Miami, Florida, USA) described how of gemmology. William Hanneman (Monterey, Califor- gemmological knowledge has helped make him money nia, USA) announced that the award is being given to when dealing with diamonds, including faceting the gir- two recipients, John I. Koivula (Gemological Institute of dle of a 6.4 ct round brilliant to improve its colour grade America [GIA], Carlsbad, California) and Alan Hodgkin- from H to G; buying brown type IIa diamonds that can son (Ayrshire, Scotland). The AGA Gala took place later be decolourized through high-pressure, high-tempera- that evening, where The Antonio C. Bonanno Award for ture treatment, so they can be sold (with disclosure) for Excellence in Gemology was presented to Al Gilbertson more money; and requesting that a laboratory recheck a (GIA, Carlsbad). This honour recognized Gilbertson’s diamond that had received a borderline I1 clarity grade, many contributions to gemmology, which included au- resulting in a considerably more valuable SI2 grade. thoring the book titled American Cut—The First 100 Years. Dr Jeffrey Post (Smithsonian Institution, Washing- Published in 2007, it recently became available for free ton DC, USA) chronicled the history of the Hope dia- download at https://archive.org/details/AmericanCut-- mond, a 45.52 ct type IIb blue diamond at the Smith- theFirst100YearsTheEvolutionOfTheAmericanCutDiamond. sonian Institution, and then described his scientific Brendan M. Laurs FGA

GIT 2016

The Gem and Jewelry Institute of Thailand’s 5th Inter- entations over two days in two parallel sessions, as well national Gem and Jewelry Conference, GIT 2016, was as 46 poster presenters. Those oral presentations that held in Pattaya, Thailand, 14–15 November 2016. It the authors attended are reported here, and abstracts included a pre-conference field trip to Mogok, Myan- of all the presentations are available in the conference mar (see report on pp. 436–443 of this issue), and a proceedings volume, which can be downloaded at post-conference excursion to the Chanthaburi-Trat area www.git.or.th/download/GIT2016.pdf. of Thailand. The conference was well attended, with GIT’s Chairman of the Board of Directors Siripol 306 participants that included 185 Thai nationals and Yodmuangcharoen and Director Dr Pornsawat 121 others from 33 countries. There were 84 presenters Wathanakul delivered brief welcoming speeches to (e.g. Figure 2) consisting of four keynote speakers, four open the conference. Gem-cutting specialist Victor invited speakers and 30 others who delivered oral pres- Tuzlukov (Moscow, Russia) gave the first keynote

Figure 2: GIT 2016 conference organizers and presenters gather for a group photo. Courtesy of GIT.

Conferences 445 Conferences

speech, titled ‘The fourth “C”: Today and tomorrow’, in production. Certainly, consumer awareness also pro- which he described changes in the gem-cutting market. pelled the value of coloured diamonds over the past 40 Modern gem-cutting techniques are becoming more years. George Lu (CIBJO Coral Commission and Chii and more precise (down to the micrometre). Tuzlukov Lih Coral Co., Taipei, Taiwan) pointed out that the coral described in detail the judging criteria of the United used as a gem material is not the same as the coral reefs States Faceters Guild and showed photos of beautifully where most people go snorkelling. The gem faceted topaz, , , kunzite, come from much deeper waters, ranging from several and a 219 ct amethyst with 705 facets. Cynthia Un- hundred metres to 1,800 m. He went on to describe the ninayar (Jewelry Showcase Magazine, New York, New taxonomy of corals from various localities and included York, USA) gave the second keynote lecture titled ‘The some amazing images of coral carvings and jewellery dozen dominant design directions for fine jewelry in from various cultures around the world. Dr Pornsawat 2017’, in which she described the trending design di- Wathanakul described GIT’s many years of research rections as: Mesmerizing Multicolors, Nature’s Glory, on the colour grading of ruby and sapphire. She pre- Lusciously Lacy, All About Anglez, Circular Momentum, sented GIT’s Masterstone sets for ‘pigeon’s blood’ ruby, Gothic Chic, Evolving Earwear, Fun Finger , ‘royal blue’ sapphire and ‘cornflower blue’ sapphire in Trendy Tassels & Fringe, Wristeria, Long & Layered and terms of the Munsell system, as well as displaying the Eco-Jewels. She also discussed Pantone’s prediction of Masterstone sets on site during the conference. She also 2017 fashion colours and the corresponding gem variet- described the importance of a standard lighting system ies. For the third keynote lecture, Dr Gaston Giuliani used in the colour-grading environment. (Institute of Research for Development, Vandœuvre- The contributed papers were organized into six lès-Nancy, France) gave detailed information about sessions: Gem Deposits and Identification; Diamonds; the geological environment, timing and geographical Corundum and Others; Pearls and Others, Innovation distribution (in terms of paleogeography and modern and Instrumentation; and Jewelry Trend and Design. geography) for the most important ruby and sapphire Dr Lore Kiefert (Gübelin Gem Lab, Lucerne, Switzer- deposits. This fundamental research provides important land) described the results of her lab’s country-of-origin background knowledge for country-of-origin determi- study on . She specified the two major geo- nations. The fourth keynote speech was delivered by logical environments in which these formed: Rupak Sen (, Mumbai, India), who provid- serpentinite-related and skarn-related. She went on to ed a detailed historical account of a shift in popularity characterize the corresponding differences in inclu- from diamonds to coloured stones and the passion for sions, spectral features and chemical composition, and them in Asian countries. He emphasized the fact that provided further details about demantoid from specific not only are celebrities taking the lead in this change, localities, as well as the heat treatment of Russian ma- but people are now saying ‘I do’ with coloured stones. terial. Tasnara Sripoonjan (GIT) reported on purple He then updated the delegates on Gemfields’ projects from Mozambique, including inclusion fea- and initiatives around the globe, including an ethical tures, spectral characteristics and the cause of colour. mining and marketing policy to help ensure the future Adesoji Adesugba (Gemstones Miners and Market- of the coloured stone industry. ers Association of Nigeria, Abuja) described the gem Among the invited speakers, Didier Giard (Associa- deposits and investment incentives in Nigeria. Dr Ah- tion Française de Gemmologie, Paris, France) described madjan Abduriyim (Tokyo Gem Science and Kyoto a shift in the paradigm of the gem and jewellery trade University, Japan) highlighted jadeite from Itoigawa, from being more production oriented toward an em- Japan, and reported the textural, chemical and spec- phasis on sustainable development. He also proposed tral characteristics in comparison with jadeite from an idea for a United Nations ‘International day for the Myanmar, Guatemala and Russia. Prof. Guanghai Shi sustainable management of the gem mines and pearl (China University of Geosciences, Beijing) described farms’, which would focus on the traceability of prod- the geology of placer deposits in the southern ucts, energy efficiency and mining regulation. He con- Xinjiang area. He then compared the ‘shan’ (primary) tinued with three more proposals, for the establishment material and ‘zi’ (placer) material in terms of the appear- of a ‘rainbow passport’, an international platform for ance and the price of the finished products. Dr Visut exchange, as well as possible financial actions.Francis Pisutha-Arnond (GIT) gave a presentation for Dr Errera (Francis Errera Ltd., Hong Kong) summarized Henry Hänni (GemExpert, Basel, Switzerland) on the the pricing and marketing of coloured diamonds from gemmological properties of ‘Sannan Skarn’ from Paki- the 1970s to 2010s. In 1976, coloured diamonds were stan, a relatively new gem material that resembles maw- cheaper than colourless diamonds. The market changed sit-sit. Arent Heilmann (Ministry of Mineral Resources, after 1986 when the Argyle mine in Australia started Nuuk, Greenland) explained the occurrence, colour

446 The Journal of Gemmology, 35(5), 2017 Conferences

and tenebrescence, fluorescence and mining of tugtup- ite from Greenland. Dr Jayshree Panjikar (Panjikar Gem Research & Tech Institute, Pune, India) reported her study of sphene from Mettur Taluk, southern India. John Chapman (Gemetrix, Perth, Australia) ex- amined how the details of lighting, viewing angle, cutting and colour zoning can affect the colour grad- ing of coloured diamonds. Seung Kwon Lee and Jo Eun Ok (Wooshin Gemological Institute of Korea, Seoul, South Korea) reported their research on coated- colour diamonds and identification techniques for near- colourless melee-sized synthetic diamonds. Dr Dietmar Schwarz (Federated International GemLab, Bangkok) and Saengthip Saengbuan- gamlam (GIT) both provided insights into determining Figure 3: Dr Ewa Wagner-Wysiecka discusses how infrared the geographic origin determination of blue sapphires. spectral features can help separate from amber. Courtesy of GIT. Thanong Leelawatanasuk (GIT) described ‘golden sheen’ and non-sheen sapphires from Kenya, highlight- ing the gemmological characteristics and microscopic sity of Technology, ; Figure 3) reviewed infra- features. Nguyen Ngoc Khoi (Hanoi University of Sci- red spectral features that can help separate copal from ence, Vietnam) provided an update on ruby and sap- amber. Dr Nirawat Thammajak (Synchrotron Light phire from Vietnam, and classified them into marble, Research Institute, Nakhon Ratchasima, Thailand) cov- gneiss and basalt types. Hyunmin Choi (Hanmi Gem- ered the radiation treatment of cultured pearls and the ological Institute & Laboratory, Seoul) described blue use of synchrotron X-ray absorption spectroscopy for sapphires before and after high-pressure, high-tem- gemmological applications. Dr Chatree Saiyasombat perature enhancement, as well as the use of Fourier- (Synchrotron Light Research Institute) described a mul- transform infrared spectroscopy for identifying this tiple-X-ray-techniques beamline that he is developing treatment. Thitikorn Na Nan (Chiang Mai University, for gemmological research applications. Thailand) described blue lead-glass-filled sapphires. Although presentations from the poster session Dr Tobias Häger (Centre for Gemstone Research, are not covered here, three posters received special Johannes Gutenberg-University of Mainz, Germany), recognition in a poster competition: (1) Meenu Brijesh characterized strontium aluminate that shows strong Vyas (Gem Testing Laboratory, Jaipur, India) described phosphorescence and has been sold as . green spinel from , (2) Sungjae Kim (Han- Nicholas Sturman (GIA, Bangkok) used real-time yang University, Seoul) presented a colour-origin study X-ray microradiography and X-ray computed micro- of various beryls and (3) Charuwan Khowpong (GIA, tomography to characterize non-bead cultured pearls Bangkok, Thailand) described the diversity of rubies from the Mergui Archipelago of Myanmar. Kook Whee from Kenya. Kwak (Wooshin Gemological Institute of Korea) de- Conference attendees celebrated the Festival of Loy scribed the identification of dyed golden South Sea Krathong, where prayers and wishes were set afloat cultured pearls using ultraviolet-visible and photolu- in ‘krathongs’ made with banana leaves and decorated minescence spectroscopy. Geng Li (School of Gems, with flowers, candles and incense. The celebration took China University of Geosciences, Beijing) explained place on the night of the ‘super moon’, the closest full the cultivation and the market for Chinese freshwa- moon to Earth since 1948, which was the inspiration for ter cultured pearls, covering both historic and current the conference theme of ‘The Fullmoon of GEMUnity’. production. Sutas Singbamroong and Aisha Rashid Prof. Andy H. Shen ([email protected]) Almazrooei (Gemstone and Labora- Gemmological Institute, China University tory, Dubai Central Laboratory, United Arab Emirates) of Geosciences, Wuhan, China presented the microradiographic structures of natural Miro Ng non-nacreous pearls from Tridacna species. Guild Gem Laboratories, Hong Kong Dr Andreas Burkhardt (Zollikon-Zürich, Switzer- land) covered state-of-the-art energy-dispersive X-ray Barbara Wheat fluorescence instruments and techniques for chemical Asian Institute of Gemological Sciences analysis. Dr Ewa Wagner-Wysiecka (Gdansk Univer- Bangkok, Thailand

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Jewelry Industry Summit 2017

The second Jewelry Industry Summit—The Open Fo- 1. Generate broad-based awareness of facts related rum on Sustainability & Responsible Sourcing in the to the jewellery industry supply chain and re- Jewelry Industry was held in Tucson, Arizona, USA, 29– sponsible sourcing, and explore what works and 30 January 2017, just prior to the AGTA GemFair. This what does not. year’s conference brought together 125 attendees (Fig- 2. Learn about and review progress on current ure 4) from many industry groups, including miners, industry-wide initiatives and developments relat- gem dealers, designers, appraisers, retailers, gemmo- ed to sustainable business practises and respon- logical educators, laboratory personnel, government sible sourcing. representatives and members of non-governmental or- 3. Develop shared visions for key segments of the ganizations. Holding the Summit just prior to the Tuc- jewellery-industry supply chain that support the son gem shows allowed for a diverse representation broader industry vision for sustainable business from many sectors of the industry. and responsible sourcing. A vision was developed at the first Jewelry Industry 4. Design prototypes of tools and strategies that Summit (held in 2016; see The Journal, 35(1), enable businesses in the supply chain to make 71–73) that merged ideas from all the participants, and progress through continuous improvement. can be summarized into four categories: To effectively explore and reach the objectives, the 1. Procure products in a manner that protects and firm Innovation Partners International was hired to help sustains the environment and respects and bene- guide participants. After an initial interview session, at- fits the people and communities where these tendees were asked to form groups to discuss what products are found. they felt was working and gather examples within or 2. Use business methods and engage in actions de- outside our industry that may be beneficial for others signed to promote and sustain growth and devel- to hear. The next task was to identify the biggest chal- opment of the people and communities where lenges each segment of our industry faces regarding products are sourced, manufactured, traded and sustainability and responsible sourcing. Finally, partici- sold. pants were asked what they could do within their con- 3. Continue to take affirmative steps towards ensur- trol that would have a ripple effect on their personal ing legal compliance, transparency and open and segment of the industry. legitimate business practises by actively engag- Throughout the Summit, several speakers provid- ing in and managing everyday actions through ed tangible examples of efforts other industries were the business supply chain. employing to address sustainability and corporate re- 4. Commit to existing international standards sponsibility. Lisa Manley (Cone Communications, Bos- including the UN Guiding Principles on Human ton, Massachusetts, USA), who served six years as global Rights and OECD Guidelines for Multinational sustainability communications director for The Coca- Enterprises. Cola Company, described her work as a sustainability The primary objective of the second summit was to consultant for clients such as Converse, CVS, Hilton, continue to collaborate and collectively engage with Mars, Quaker, Target, Timberland, U.S. Bank, Wrigley members of all sectors of the industry to help further and others. She emphasized that it is okay for busi- the vision principles outlined above. The four main nesses to take an advocacy stance, and millennials ex- goals were: pect companies to adhere to ethical business practices.

Figure 4: The second Jewelry Industry Summit brought together 125 attendees from various industry groups. Photo by Mariana Photiou.

448 The Journal of Gemmology, 35(5), 2017 Conferences

She cited sustainable business trends such as transpar- ency, collaboration, human rights initiatives, recycling, etc. She challenges her clients to be conscientious, con- nected to communities where they source and sell, and be radically inclusive and inspiring. Tangible examples include water stewardship, sustainable packaging, climate protection and supporting sustainable commu- nities through women’s economic empowerment and active, healthy living. Thea Polancic (Clear Space, Chi- cago, Illinois, USA) gave a passionate presentation on ‘Conscious Capitalism’ to relay the power of business to create prosperity, beauty and happiness in the world. The Conscious Capitalism movement was popularized Figure 5: Summit participants broke into small groups to by John Mackey, CEO of Whole Foods, and is dedicat- discuss visions for the future of the jewellery industry and ed to elevating humanity through business. This move- to identify actionable tasks to bring those visions to reality. ment has gained ground rapidly, and Polancic runs the Here, Dr Girma Woldestinsae and Anna Barker review notes Chicago chapter, which has grown to 1,100 members from their group. Photo by E. Boehm. in 18 months. The main tenets of the movement are to focus on a higher purpose, create value for all stake- ences educating and encouraging rural school children holders, encourage caring and passionate leadership, to look for minerals and gems on their way to and and create healthy and value-based cultures. from school. Teachers are asked to form science and Participants were then asked to gather in small groups coloured-stone clubs through which they can integrate to create compelling visions for the future of our indus- their teaching curricula to educate their students about try and to identify real actions we could take to bring the characteristics and properties of the rocks and min- those visions to fruition (e.g. Figure 5). Each group then erals they find. They also focus on stories that encour- presented their visions to the entire audience. The end age thinking about creating added value and turning of the first day concluded with a cocktail reception and raw materials into useful products. To assist his project, poster session, which featured more than 20 presenters. we proposed providing gemmological training and in- The second day of the Summit began with a presen- strumentation, as well as translating into local languag- tation by Bob Mitchell (Electronic Industry Citizenship es the Gemological Institute of America’s new guide to Coalition [EICC], Alexandria, Virginia, USA). Mitchell is gem rough booklet that has already been introduced to a 16-year veteran of Hewlett Packard with more than 10 rural mining communities in Tanzania. years in sustainability. He was most recently the Director Along with new ideas, a number of initiatives initially of Global Social & Environmental Responsibility at introduced at the first Summit were reintroduced for up- Hewlett Packard Enterprise, where he led a team of date and further review. For example, Eric Braunwart professionals in human rights, supply-chain responsi- (Columbia Gem House, Vancouver, Washington, USA) bility and conflict minerals. Mitchell shared examples and his committee shared developments on eliminating of his experiences at Hewlett Packard and the EICC silicosis. His initiative proposes education and use of mission and values of a responsible global electronics equipment designed to reduce exposure to ultra-fine supply chain. The EICC consists of more than 100 elec- particulates from mining and cutting that are known to tronics companies, has a combined revenue of more cause silicosis. His committee presented several pos- than US$4.75 trillion and directly employs more than sible technological developments that would reduce 6 million people. Their primary focus is on ethical and exposure during the cutting and polishing of beads. conflict-free sourcing of raw materials and labour. Another initiative from the first Summit focuses on The attendees were then asked to identify ac- mining of rutilated quartz in a remote region of , tion possibilities that they could personally explore Brazil. This responsible sourcing initiative aims to and implement. The author’s group was inspired create a model artisanal and small-scale (ASM) mining by one of the poster presentations—by Dr Girma community that would serve as a guide for other ASM Woldestinsae (Ministry of Mines, Petroleum and communities. Brian Cook (Nature’s Geometry, Tuc- Natural Gas, Addis Ababa, Ethiopia)—to provide son) proposed empowering the rural rutilated-quartz- basic resources and education to students in rural mining community by constructing a processing ware- areas, in order to help them learn about and identify house and lapidary school. He also plans to help the potential local natural resources. In his presentation, miners and their families create greater food security Dr Woldestinsae enthusiastically shared his experi- through the development of organic farming.

Conferences 449 Conferences

Five new initiatives were introduced along with the initiative’s goals and helped each group gain additional eight initiatives from the first Summit, so participants support and create a prototype that the group could divided into 13 teams. Attendees were encouraged to confidently present to the entire Summit. The initiatives migrate to the initiatives that interested them most to and their descriptions, progress, next steps, challenges hear their goals and provide input. Group leaders gave and resources needed, will be shared via the Jewelry brief presentations and conducted discussions with Industry Summit’s website www.jewelryindustrysummit. teammates and those who joined in. Participants were com, Facebook page jewelryindustrysummit and on In- encouraged to visit as many different groups as possi- stagram at #ResponsibleJewelryStories. ble and focus on how to overcome challenges and ob- Edward Boehm FGA ([email protected]) stacles. This process allowed further refinement of each RareSource, Chattanooga, Tennessee, USA

Letters

Comment on the Apparent Anomalous Reflectance of a Sumitomo Synthetic Diamond

In the previous issue of The Journal, Hodgkinson of the incident illumination is reflected from the top (2016) reported observations that he and a colleague surface. The rest of the light enters the diamond, and had made on a Sumitomo high-pressure, high-tem- about 17% of the light that reaches the rear surface is perature (HPHT) synthetic diamond using a Hanne- also reflected. The reflected light from both the top man Diamond Eye reflectance meter. The reading ob- and bottom faces travels back along the path defined tained from that sample was much higher than that by the incident illumination. For a colourless diamond, obtained from a control sample of natural diamond. the total intensity of the reflected light is about 29% We show below that this ‘anomalous behaviour’ has of the incident intensity. (This value is obtained by its origin in the different geometries of the natural taking into account the multiple reflections that occur and synthetic diamonds used in that investigation. within the diamond plate.) If the diamond is coloured, The former was faceted as a round brilliant, where- as with the HPHT synthetic studied by Hodgkinson as the Sumitomo sample was a thin polished plate. (2016), some light will be absorbed internally, and The reflectance R in air from the polished surface there is a smaller contribution from the rear surface; of an optical material is approximately given by R = however, the total intensity of the reflected light will (n – 1)2/(n + 1)2, where n is the refractive index of still be much greater than that observed from the ta- the material. For diamond R = 0.172 at the ‘sodium D’ ble of a round brilliant. That is why, in Hodgkinson’s wavelength (589.3 nm). Consider a thin pencil of light investigation, “the indicator needle [of the Hanneman incident normally on the table of a round brilliant. reflectance meter] raced across the scale beyond ‘dia- Approximately 17% of the light is reflected back along mond’ to the extremity of the instrument”. the path defined by the incident illumination. The rest Prof. Alan T. Collins of the light enters the diamond where it is refracted Department of Physics, King’s College London and reflected in numerous directions. Very little, if any, Reference of that light travels back along the path defined by the Hodgkinson A., 2016. Anomalous behaviour of a incident illumination. Sumitomo synthetic diamond on the reflectance For a thin plate of diamond, with near-parallel meter. Journal of Gemmology, 35(4), 274–275, polished top and bottom faces, approximately 17% https://doi.org/10.15506/jog.2016.35.4.274.

450 The Journal of Gemmology, 35(5), 2017 Gem-A Notices

GIFTS TO THE ASSOCIATION

The Association is most grateful to the following for their gifts and donations for research and teaching purposes:

Meg Berry, Fallbrook, California, USA, for pieces Mauro Pantò, The Beauty in the Rocks, Sassari, of green garnet from Ethiopia. Italy, for a buff-top quartz with chlorite inclu- Guy Borenstein FGA, Gemewizard, Ramat Gan, sions from Brazil. Israel, for Gemewizard monitor calibration kit Werner Radl, Mawingu Gems, Niederwörres- containing six faceted pieces of terbium glass. bach, Germany, for one quartz sphere with Dr Marco Campos Venuti, Seville, Spain, for a inclusions from Kongwa District, Tanzania. faceted pollucite with polylithionite inclusions Helen Serras-Herman FGA, Gem Art Center, from . Rio Rico, Arizona, USA, for a ‘Mohave Purple Jeffrey Bergman, Primagem, Bangkok, Thailand turquoise’ composite stone. for two trapiche ruby specimens from India Leonardo Silva Souto, Cosmos Gems, Minas consisting of a hexagonal flat cabochon and Gerais, Brazil, for a quartz cabochon with a crystal. inclusions from , Brazil. Farooq Hashmi, Glen Cove, New York, USA, for Steve Ulatowski, New Era Gems, Grass Valley, two cabochons from Pakistan. California, USA, for a Cr-bearing dravite crys- Syed Iftikhar Hussain, Syed Trading Co., tal from Tanzania. Peshawar, Pakistan, for four cab- Charles Vargas, Apache Gems, San Carlos, ochons from Australia, and a faceted quartz Arizona, USA, for three pieces of rough with actinolite needles from Pakistan. ‘Apache Blue stone’ from the Apache Nation, Marc Jobin, New York, New York, USA, for Arizona. three spheres of rainbow moonstone from Tak Yi Yung FGA, Shau Kei Wan, Hong Kong, Madagascar. for a monetary donation. Mona Khan, Vista Gems, Skillman, New Jersey, USA, for a cabochon of ‘Passion amethyst’ from Minas Gerais, Brazil. National Association of Jewellers, London, for OBITUARY a box of paste replicas of famous diamonds, three sets of fashion diamond imitations dis- Evelyn (Eve) Rosemary Symes FGA DGA playing different shapes and sizes, and four (D.2002 and 2007), Bath, Somerset, passed away teaching sets of NAJ education stones con- on 6 December 2016. Eve was Treasurer of the taining more than 200 various rough and cut South West Branch of Gem-A for a number of specimens. years.

Gem-A Notices 451 Learning Opportunities

CONFERENCES AND SEMINARS

44th Rochester Mineralogical Symposium The Gemmological Society of Japan Conference 20–23 April 2017 10–11 June 2017 Rochester, New York, USA Tokyo, Japan www.rasny.org/minsymp www.gakkai.ac/gsj/english Scottish Gemmological Association Conference XVIèmes Rendez-Vous Gemmologiques de Paris 28 April–1 May 2017 12 June 2017 Stirling, Scotland Paris, France www.scottishgemmology.org/conference www.afgems-paris.com/rdv-gemmologique 3rd Mediterranean Gemmological and PEG2017—8th International Symposium on Jewellery Conference Granitic Pegmatites 11–14 May 2017 13–15 June 2017 Syracuse, Italy Kristiansand, www.gemconference.com www.nhm.uio.no/forskning/aktuelt/arrangementer/ Note: The conference theme is coloured diamonds, konferanser-seminarer/peg2017/ and the programme will include several speakers, a round table discussion, pre-conference workshops Scandinavian Gem Symposium 2017 and a poster competition. 17–18 June 2017 Kisa, 5th Annual Mineral Conference http://sgs.gemology.se 12–14 May 2017 Newry, , USA Sainte-Marie-aux-Mines 54th Mineral & Gem Show www.nemineralconference.org/nema 22–25 June 2017 Sainte-Marie-aux-Mines, France The 31st Annual Santa Fe Symposium www.sainte-marie-mineral.com/english/modules/ 21–24 May 2017 cultural-activities Albuquerque, , USA Note: Includes a symposium and lectures. www.santafesymposium.org Tourmaline 2017 2017 Society of North American Goldsmiths 23–28 June 2017 Conference Nové Město na Moravě, Czech Republic 24–27 May 2017 www.tourmaline2017.cz New Orleans, Louisiana, USA www.snagmetalsmith.org/events/conferences Swiss Gemmological Society Conference and European Gemmological Symposium 2017 11th International Conference on New Diamond 29 June–1 July 2017 and Nano Zermatt, Switzerland 28 May–1 June 2017 http://gemmologie.ch/en/current/messages/central- Cairns, Queensland, Australia course-egs-2017.php http://ndnc2017.org Northwest Jewelry Conference JCK Las Vegas 11–13 August 2017 5–8 June 2017 Seattle, Washington, USA Las Vegas, Nevada, USA www.nwjcon.com http://lasvegas.jckonline.com/en/Events/Education © Note: Includes a seminar programme. 48th ACE IT Annual Mid-Year Conference 12–15 August 2017 Association for the Study of Jewelry and Related Indianapolis, Indiana, USA Arts (ASJRA) Annual Conference www.najaappraisers.com/html/conferences.html 9–10 June 2017 Boston, Massachusetts, USA Dallas Symposium www.jewelryconference.com 25–27 August 2017 Dallas, Texas, USA Compiled by Angharad Kolator Baldwin and Brendan Laurs www.dallassymposium.org

452 The Journal of Gemmology, 35(5), 2017 Learning Opportunities

28th International Conference on Diamond and Session of interest: Natural Stone in History of Materials (DCM 2017) Civilization (Including Gemology) 3–7 September 2017 Gothenburg, Sweden Friends of Mineralogy Pacific Northwest Chapter www.diamond-conference.elsevier.com 43rd Annual Symposium: Minerals of the Pacific Northwest Hong Kong Jewellery & Gem Fair 13–15 October 2017 13–19 September 2017 Kelso, Washington, USA Hong Kong www.pnwfm.org/symposium http://tinyurl.com/hbn8y56 Note: Includes a seminar programme. Canadian Gemmological Association Conference 20–22 October 2017 Denver Gem & Mineral Show Toronto, Canada 15–17 September 2017 www.canadiangemmological.com/index.php/com- Denver, Colorado, USA virtuemart-menu-configuration/conferences-and- www.denvermineralshow.com special-events Note: Includes a seminar programme. ICA Congress IRV Loughborough Conference 16–18 September 2017 21–24 October 2017 Loughborough Jaipur, India www.jewelleryvaluers.org/Loughborough-Conference www.gemstone.org (to be announced on new website) 11th International Kimberlite Conference Geological Society of America Annual Meeting 18–22 September 2017 22–25 October 2017 Gaborone, Botswana Seattle, Washington, USA www.11ikc.com www.geosociety.org/GSA/events/GSA2017 Note: Pre- and post-conference field trips will visit Session of interest: Gemological Research in the diamond deposits in Botswana and neighbouring 21st Century: Characterization, Exploration, and countries. Geological Significance of Diamonds and Other Gem Minerals. World of Gems Conference V 23–24 September 2017 9th International Congress on the Application Rosemont, Illinois, USA of Raman Spectroscopy in Art and Archaeology http://gemguide.com/events/world-of-gems-conference 24–28 October 2017 Note: Includes a poster session, and pre- and post- Évora, Portugal conference workshops. www.raa2017.uevora.pt

ASA 2017 International Appraisers Conference The Munich Show 7–10 October 2017 27–29 October 2017 Houston, Texas, USA Munich, Germany www.appraisers.org/education/conferences www.munichshow.com/en 200th Anniversary Meeting of the Russian Note: Includes a seminar programme. Mineralogical Society Gem-A Conference 10–13 October 2017 4–5 November 2017 Saint Petersburg, Russia London www.minsoc.ru/2017 www.gem-a.com

EXHIBITIONS Asia Treasures of the Natural World: Best of Mastery of an Art: Van Cleef & Arpels: London’s Natural History Museum High Jewelry and Japanese Crafts Until 11 June 2017 29 April–6 August 2017 National Museum of Nature and Science, Tokyo, Japan National Museum of Modern Art, Kyoto, Japan http://treasures2017.jp/outline/english_index.php http://highjewelry.exhn.jp

Learning Opportunities 453 Learning Opportunities

Europe The Taft Museum of Art, Cincinnati, Ohio, USA www.taftmuseum.org/cur_exhib Across Art and Fashion Until 7 April 2017 Playa Made: The Jewelry of Burning Man Museo Salvatore Ferragamo, Florence, Italy Until 4 June 2017 www.ferragamo.com/museo/en/usa/exhibitions Fuller Craft Museum, Brockton, Massachusetts, USA http://fullercraft.org/event/playa-made-burning-man- De Vroomen: Harmony in Colour and Form jewelry 12 April–26 July 2017 Goldsmiths’ Hall, London Spectacular! Gems and Jewelry from the www.thegoldsmiths.co.uk/company/today/ Merriweather Post Collection events/2017/de-vroomen-harmony-colour-and-form 10 June 2017–1 January 2018 Warrior Treasures: Saxon Gold from the Hillwood Estate, Museum & Gardens, Washington Staffordshire Hoard DC, USA Until 23 April 2017 www.hillwoodmus eum.org/Spectacular-Gems-and- Bristol Museum & Art Gallery, Bristol Jewelry www.bristolmuseums.org.uk/bristol-museum-and-art- Past Is Present: Revival Jewelry gallery/whats-on/warrior-treasures Until 19 August 2019 Authentically Inauthentic?—Jewellery from Museum of Fine Arts, Boston, Massachusetts, USA Pforzheim’s Industrial Production www.mfa.org/exhibitions/past-is-present-revival- 21 May–10 September 2017 jewelry Municipal Museum, Pforzheim, Germany www.schmuckmuseum.de/flash/SMP_en.html The Wonderful World of Until December 2017 Must-haves—Jewellery Created by Greats of the New Mexico Museum of Natural History & Science, Craft and Must-sees—Jewellery in the Arts Albuquerque, New Mexico, USA 21 May–10 September 2017 www.nmnaturalhistory.org/exhibits/temporary- Schmuckmuseum, Pforzheim, Germany exhibits/wonderful-world-opals www.schmuckmuseum.de/flash/SMP_en.html Gilded New York Tone Vigeland. Jewelry–Object–Sculpture Ongoing Until 11 June 2017 The Design Museum, Munich, Germany Museum of the City of New York, New York, USA http://dnstdm.de/en/tone-vigeland-schmuck-objekt- www.mcny.org/exhibition/gilded-new-york skulptur-2 Mightier than the Sword: The Allure, Beauty Stone of Heaven. HRH Prince Henrik’s and Enduring Power of Beads Collection of Oriental Jade Ongoing Until 27 August 2017 Yale Peabody Museum of Natural History, Museet på Koldinghus, Kolding, Denmark New Haven, , USA www.koldinghus.dk/uk/exhibitions-2017/stone-of- http://peabody.yale.edu/exhibits/mightier-sword- heaven.html allure-beauty-and-enduring-power-beads Vanity: Stories of Jewelry in the Cyclades Until September 2017 Archaeological Museum of Mykonos, Mykonos, Greece Australia and New Zealand http://odysseus.culture.gr/h/4/eh41.jsp?obj_id=23576 Jewellery—From Decorative to Practical Australian Exhibition Ongoing 3–4 August 2017 Nordiska Museet, Stockholm, Sweden Surfers Paradise, Queensland, Australia www.nordiskamuseet.se/en/utstallningar/jewellery www.austopalexpo.com.au The House of Dior: Seventy Years of Haute Couture North America 27 August–7 November 2017 Bijoux Parisiens: French Jewelry from the Petit The National Gallery of Victoria, Melbourne, Palais, Paris Australia Until 14 May 2017 www.ngv.vic.gov.au/exhibition/the-house-of-dior

454 The Journal of Gemmology, 35(5), 2017 Learning Opportunities

OTHER EDUCATIONAL OPPORTUNITIES

Gem-A Workshops and Courses Lectures with The Society of Jewellery Gem-A, London Historians www.gem-a.com/education/courses Society of Antiquaries of London, Burlington House, London Gem-A Midlands Branch www.societyofjewelleryhistorians.ac.uk/current_lectures Fellows Auctioneers, Birmingham Email [email protected] • 27 June 2017 Andrew Prince—Sparkling Times and My Work • 21 April 2017 (please note the change in date) So Far Elizabeth Goring—Suffragette Jewellery • 26 September 2017 DUG Advanced Gemology Program (in English) (40th Anniversary Lecture) 6 November–8 December 2017 Paulus Rainer—Benvenuto Cellini’s Salt Cellar: Nantes, France Some New Thoughts, Some New Discoveries www.gemnantes.fr/en • 24 October 2017 Gemstone Safari to Tanzania Lynne Bartlett—The Rise and Fall of the 8–25 January 2018 Morogoro, Umba, Arusha, Longido, Merelani and Lake Manyara, Tanzania • 28 November 2017 www.free-form.ch/tanzania/gemstonesafari.html Judy Rudoe—Cartier Gold Boxes: A Visionary Note: Includes options for a lapidary class and/or a Patron and a Bet with Ian Fleming private trip to visit ruby mines near Morogoro and Mpwapwa (including Winza).

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● Full of up-to-date information on the latest news and trends ● Exclusive features ● Regular reports from gemmology insiders ● Highlights from our printed publications ● Behind the scenes at Gem-A and industry events

Our top performing blog post from last month? The Journal Digest from Volume 35/No.4/2016 ‘Ruby and Pink Sapphire from Aappaluttoq, Greenland’.

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Learning Opportunities 455 Gem-A Conference 2017 Saturday 4 and Sunday 5 November etc.venues County Hall, Westminster Bridge, London

1 New Media

New Media

Gem—The Definitive Visual Guide

2016. Dorling Kindersley considering all copper minerals together—is not obvi- Ltd, London, in connec- ous. There are also errors with how some minerals tion with Smithsonian are categorized. For example, , an aluminium Books, Washington DC, , is listed out of order on page 104 with the USA, www.dk.com/ carbonates. us/9781465453563-gem, Regarding the book’s words, these are found in 440 pages, illus., several blocks on the characterization pages: main ISBN 978-1465453563. text, characterization box, figure captions, figure £25.00 hardcover. labels and a pithy quote. Among my issues with the words: • Regarding the treatments mentioned on page Beware of a book with multiple editors and no rec- 31, laser drill holes in diamonds are much like- ognized authors. (Five contributors, listed in the ac- lier to be filled with a high-RI glass than with knowledgments, are presumably responsible for the epoxy resin. text of this large volume; but the masthead lists 13 • Page 23: Absorption spectra depend not only editors, exclusive of additional editor named on the on specific (chromophore) elements, but also cover.) With no single person responsible, but many their local environment (chromium causes people ‘in charge’, facts and meanings can get lost. different spectra in ruby, red spinel and red In a book review, it is traditional to indicate whether garnet, not to mention green emerald). And the reviewer liked or disliked the book. I wanted to there are other causes for absorption besides like this book, but it pains me to note that this guide chromophores, such as the structural defects to gems, while beautiful, is by no means definitive. In- in pink diamonds. stead, it is fraught with errors and mischaracterizations. • Pages 44 and 48: For some reason, RI values There are three main aspects to such a guide book: are given for platinum and copper. Since met- its organization, its words and its images. All three als are opaque (except in very thin sections), it have problems, as well as some positive aspects. would be more meaningful to provide reflec- I have several comments on the book’s organiza- tivity, or to omit such values entirely. tion. The book alternates gem characterization pages • Page 71: Sapphire does not have adamantine (or two-page spreads) with descriptive pages about lustre, but rather vitreous. jewellery history or specific jewels. This is a strong • Page 88: localities are listed in two positive feature, since the jewellery pages are any- places and the lists do not match. thing but boring and are profusely illustrated. As jew- • It is unlikely that synthetic topaz was used in the ellery and its history are not areas of my expertise, restoration of the Patiala Necklace (page 91), as I am not competent to find errors on these pages this was not yet a commercially significant ma- and they read very well for me. The characteriza- terial in gem quality, and natural (and treated) tion pages, however, tended to catch my eye for their topaz was both plentiful and inexpensive. errors, inconsistencies or odd placement. These pag- • Page 98: When stating, “Calcite has the largest es are divided into the following categories: Native number of different crystal structures of any Elements, Gemstones, Organic Gems, and Rock Gems mineral…”, it should say crystal habits here. and Rocks. This is an unfortunate way to slice up Calcite has only one . the ‘gem universe’, since the only non-metallic na- • There is an error in transcribing ancient Greek tive element considered is diamond, and the ordering on page 117: ‘gonia’ (gonia) means angle, not scheme (which follows the Dana system) does not ‘gouia’. start with the most important gems, but with rather • Page 157: ‘Black onyx’ is not onyx, which is insignificant ones. (If you were looking in a gem book striped; it is instead heat-treated porous chal- for the characteristics of diamond, would you look cedony. after copper and before pyrite?) Minerals are defined The publisher DK has done its usual excellent job of by their chemical compositions and their structures. images. However, I have some issues with the The book neglects even the mention of structure, so figures (mainly their captions and labels), among them: the reason for organizing gem minerals by the Dana • The size (or at least weight) of most objects in system—by anions and not cations, rather than, say, the images is not indicated.

New Media 457 New Media

• If a gem is photographed in diffuse lighting, it And the so-called padparadscha looks instead will generally not display ‘fire’ (which instead like a pink sapphire, possibly with some rust is seen when the edge of a light ray is partly staining. refracted, leading to a flash of spectral colour). • The Timur Ruby is not discernible in the famous The caption for a colourless ‘cut taaffeite gem- portrait of Queen Elizabeth II on page 78. stone’ on page 87 asserts that fire is visible, but • Page 88: The example labelled ‘Specular Hema- none is seen in the photograph. tite | Rough’ does not show specular hematite, • The causes of ‘fire’ should be discussed. Dou- which forms in flat plates. ble refraction is not the primary cause of fire, • On page 114, is given as the an- although it can help. The same is true of a high niversary gem for both the 9th year (caption RI. The main cause of fire in gemstones is dis- title) and the 7th year (text of caption). persion, the tendency of rays at the opposite • The ‘traditional triangular step cut’ on page 116 end of the visual spectrum—i.e. red and blue/ has a four-sided profile, not a three-sided one. violet—to take different paths through a gem I would call it a lozenge shape instead. because of their different refractive indices. • In the amethyst images/text on page 136, an ap- • Page 14: The example provided for carbonates parent flaw is visible in the upper left corner of is chrysocolla (a silicate, not a carbonate), with the ‘internally flawless’ step cut, and colour zon- a label pointing to chrysocolla and saying it is ing is still visible in the mixed cut, which was ‘blue ’. There is azurite (a carbonate) on supposedly fashioned to minimize this effect. the specimen, but it looks black, not blue, here. Various additional examples of mistakes or mis- • Page 21: Unless African orange sapphires are characterization have not been mentioned here. So, included in the term ‘padparadscha’, I question why these many problems? As alluded to above, this whether these gemstones are as affordable as book has no single responsible author and more than indicated on the figure. a dozen editors. But with a ‘critical mass’ of editors, the • Pages 24–25: This list of sources for the various result can be a massive game of ‘telephone’. An urgent gem varieties, while helpful, is not exhaustive. deadline and easy access to the Internet may lead the • Page 66: The ‘modified crystals’ of pyrite unwary to create a product that is ‘good enough’…but show cube and pyritohedral faces, not cube not, in this case, definitive. and octahedral faces. Dr Mary L. Johnson • On page 72, the bipyramidal ‘colourless rough’ Mary Johnson Consulting crystal is described as having prismatic shape. San Diego, California, USA

Gemstones—Terra Connoisseur

By Vladyslav Y. Yavor- of the gem being featured, with mining shots, miners, skyy, 2017. Yavorskyy rough stones and finished gems telling a story with- Co. Ltd, New York, in that page. Maps have been used throughout from New York, USA, antique prints, with colourful groups of gems and http://ivynewyork. rough on each corner (which, as an antiquarian map com/gemstonesbook, lover, I found a bit unnecessary). 235 pages, illus., The book’s contents are highlighted on pages 7–8, ISBN 978-0692784990. and even these two pages have gem photos peeking US$88.00 hardcover. out. Portions of the text are listed that have been au- thored by various experts and friends. The first 40 pag- es cover several topics, including the author’s forward, the history of gemstones, gem cutting and lighting. This is the third book in the Terra series, after spinel The history section, while succinct in its eight pages, and garnet, and it follows the style of previous Terra hit many highlights with photos reproduced from vari- works: colourful and beautiful. They have been created ous museums that are credited. The gem cutting sec- by a true artist: Yavorskyy loves nature, is a fine pho- tion is basic, but well done in 10 pages, mostly con- tographer and has travelled the world in search of his sisting of photos of gems and a few shown passion—rough gem materials. cutting as well as the related machinery. I particularly There is very little text in Gemstones, with most liked this statement: “...so the essence of the craft lies pages being full of colour. Like a kaleidoscope, photos in the preforming stage; this is when the destiny of a are often practically stacked upon each other, creating gem is shaped”. The lighting chapter consists of two a somewhat different look from the usual gem book. pages showing the different looks achieved in white The pages often show ethereal photos from the area vs. somewhat yellow light, with tips that might be use-

458 The Journal of Gemmology, 35(5), 2017 New Media

ful for interested readers trying their hand at gem pho- untreated”. Although a bit redundant, it highlights the tography. importance to the author of untreated gems. The next 44 sections cover specific gemstones that The final dozen pages briefly cover other gem -ma Yavorskyy has been involved with, ranging from dia- terials and gem properties, how to be successful in the mond to fluorite in no particular order. His stated fa- gem business, gem shows and gemstones of the future, vourite gemstone is spinel, which is covered in seven of with an index of gem varieties on the final page. the 44 sections (categorized as: rare, blue, mauve, grey, The inside front and back covers are the same: a lavender, red and pink). This gives the author many group photo of several hundred gemstones. Many are pages to feature various stories from Sri Lanka, Tanza- used throughout the book in various places, and some nia, Burma and Vietnam. Most of these are two pages are seen more often than others. long, but the red spinel chapter is 20 pages! Each of In this reviewer’s opinion, most anyone interested in the gem sections show extraordinary cut stones, photos gems will enjoy this book. Several friends saw the book of nearby areas (often at sunset) and the local peo- as I was reviewing it, and expressed interest in acquir- ple involved with gems. The hundreds of gems pho- ing a copy. They felt it was a good ‘coffee table’ book tographed—most with their carat weight listed—may to page through with an abundance of beautiful colour seem a bit like a fancy catalogue of the author’s inven- photos that anyone would enjoy. Not all gem books are tory, but with that said the gems are beauties. Repeat- this beautiful. ed on most of these pages featuring the cut stones is William F. Larson FGA printed “all [gem name] in these pages are natural and Palagems.com, Fallbrook, California, USA

OTHER BOOK TITLES Coloured Stones General Reference Asterism—Gems with a Star The Sisk Gemology Reference By Martin P. Steinbach, 2017. Self-published, 900 By Jerry Sisk, 2017. Jewelry Television, Knoxville, pages, ISBN 978-3000504945. US$199.00 hardcover. Tennessee, USA, Vol. 1: Prominent Gems, 446 pages, Ruby & Sapphire: A Gemologist’s Guide ISBN 978-0692713181; Vol. 2: Noteworthy Gems, By Richard W. Hughes, 2017. Lotus Publishing, 334 pages, ISBN 978-0692794722; Vol. 3: Gallery of Bangkok, Thailand, 816 pages, ISBN 978-0964509719. Gems, 314 pages, ISBN 978-0692794739. US$199.99 US$200.00 hardcover. hardcover with slipcase.

Diamond Jewellery and Objets d’Art Italian Jewelry of the 20th Century Botswana Diamond Jewellery By Melissa Gabardi, 2017. Silvana, Milan, Italy, 336 By Michael C. Brook, 2016. Self-published, 136 pages, ISBN 978-8836635078. £62.25 hardcover. pages, ISBN 978-9996804182. US$75.00 hardcover. Primal Beauty—The Sculptural Artistry of Diamond—The Ultimate Gemstone Crystal Works (MINERAL Monograph No. 19) By Lawrence Stoller, 2017. Cameron + Company, Ed. by Jeff W. Harris and Gloria A. Staebler, 2017. Petaluma, California, USA, 208 pages, ISBN 978- Lithographie Ltd, Arvada, Colorado, USA, 152 pages, 1944903053. US$50.00 hardcover. ISBN 978-0983632351. US$40.00 softcover. The Story of Trifari Fancy Color Diamonds: The Pricing Architecture By Maureen Brodsky, 2016. Two Pines Studio, By Eden Rachminov, 2016. Self-published, 200 pages. St Louis, Missouri, USA, 247 pages, ASIN US$240.00 hardcover. B01NBOM2XD. US$11.90 Kindle edition. Kohinoor: The Story of the World’s Most Infamous Diamond Pearls By William Dalrymple and Anita Anand, 2016. Self- published using Juggernaut, 264 pages, ISBN 978- Pearl Buying Guide: How to Identify 9386228086. US$32.95 hardcover. and Evaluate Pearls, 6th edn. By Renée Newman, 2017. International Jewelry Objective Diamond Clarity Grading Publications, Los Angeles, California, USA, 153 pages, By Michael D. Cowing, 2017. Amazonas Gem Pub- ISBN 978-0929975528. US$19.95 softcover. lications, Palma, Mallorca, Spain, 138 pages, ISBN 978-0998483702. US$19.95 ebook. The Long Road to Broome By William Reed, 2016. Allure South Sea Pearls, Broome, , 136 pages, ISBN 978- Compiled by Angharad Kolator Baldwin and Brendan Laurs 0994409928. A$29.00.

New Media 459 Literature of Interest

Coloured Stones Riondet and G. Panczer, Revue de Gemmologie A.F.G., No. 198, 2016, 25–28 (in French). Afghanit in Edelsteinqualität [Gem-quality afghanite]. U. Henn and C.C. Milisenda, Glass on the Amber Road: The chemical Gemmologie: Zeitschrift der Deutschen composition of glass beads from the Gemmologischen Gesellschaft, 65(1–2), 2016, 52–56 Age in Poland. T. Purowski, L. Kępa and B. Wagner, (in German with English abstract). Archaeological and Anthropological Sciences, 2016, 1–20, http://dx.doi.org/10.1007/s12520-016-0443-8. Amethyst of remarkable fine qualities from a reportedly new find in Rwanda. T. Stephan and F. Schmitz, Australian Gemmologist, 26(1–4), 2016, Diamonds 45–47. Diamond cleavage: Importance to high pressure research. W.A. Bassett and E.A. Skalwold, High The big band theory [agate formation]. Pressure Research, 37(1), 2016, 46–58, http://dx.doi. M. Campos-Venuti, Rock & Gem, 46(6), 2016, 16–23. org/10.1080/08957959.2016.1274979. Comparative analysis of the characteristics of Diamond growth in mantle fluids. H. Bureau, Australian opal and Ethiopian opal. J. Luo, X. Liu D.J. Frost, N. Bolfan-Casanova, C. Leroy, I. Esteve and X. Yan, Superhard Material Engineering, 28(6), and P. Cordier, Lithos, 265, 2016, 4–15, http://dx.doi. 2016, 50–57 (in Chinese with English abstract). org/10.1016/j.lithos.2016.10.004. Gemmological characteristic of amazonite from Diamonds from the Machado River alluvial Mozambique. G. Meng, M. Chen and Y. Wang, deposit, Rondônia, Brazil, derived from both Journal of Gems & Gemmology, 18(4), 2016, 28–32 (in lithospheric and sublithospheric mantle. A.D. Chinese with English abstract). Burnham, G.P. Bulanova, C.B. Smith, S.C. Whitehead, Heterosit vs. Phosphosiderit [Heterosite vs. S.C. Kohn, L. Gobbo and M.J. Walter, Lithos, 265, 2016, phosphosiderite]. T. Stephan, J. Hyrsl and 199–213, http://dx.doi.org/10.1016/j.lithos.2016.05.022. C.C. Milisenda, Gemmologie: Zeitschrift der Deutschen Regular cuboid diamonds from placers on the Gemmologischen Gesellschaft, 65(1–2), 2016, 56–60 (in northeastern Siberian platform. D.A. Zedgenizov, German with English abstract). V.V. Kalinina, V.N. Reutsky, O.P. Yuryeva and M.I. Inclusions in natural, synthetic, and treated Rakhmanova, Lithos, 265, 2016, 125–137, http://dx. emerald [chart]. N.D. Renfro, J.I. Koivula, J. Muyal, doi.org/10.1016/j.lithos.2016.04.012. S.F. McClure, K. Schumacher and J.E. Shigley, Gems Type Ib diamond formation and preservation in & Gemology, 52(4), 2016, 402–403, http://dx.doi. the West African lithospheric mantle: Re–Os age org/10.5741/GEMS.52.4.402.* constraints from sulphide inclusions in Zimmi A new find of danburite in the Luc Yen mining diamonds. K.V. Smit, S.B. Shirey and W. Wang, area, Vietnam. L.T.-T. Huong, L.M. Otter, T. Häger, Precambrian Research, 286, 2016, 152–166, http://dx. T. Ullmann, W. Hofmeister, U. Weis and K.P. Jochum, doi.org/10.1016/j.precamres.2016.09.022. Gems & Gemology, 52(4), 2016, 393–401, http://dx.doi. org/10.5741/GEMS.52.4.393.* Fair Trade Overview of garnet composition inter- Code green—B.C. jade producers work toward a relationships. G. Pearson, Australian Gemmologist, code of conduct. S.M. Dilt, Jewellery Business, 12(3), 26(1–4), 2016, 48–53. 2016, 64–66, 68, 70–71. Zultanite, l’affascinante diasporo cangiante The sustainable luxury contradiction: Evidence proveniente dalla Turchia [Zultanite, the from a consumer study of marine-cultured pearl charming colour-change diaspore from Turkey]. jewellery. J. Nash, C. Ginger and L. Cartier, Journal M. Macrì, Rivista Italiana di Gemmologia, No. 0, 2017, of Corporate Citizenship, No. 63, 2016, 73–95, http:// 12–17 (in Italian). dx.doi.org/10.9774/GLEAF.4700.2016.se.00006. Cultural Heritage Gem Localities Analyses gemmologiques sur site de la Géologie et gisements de gemmes au Sri Lanka Couronne de Notre-Dame de Fourvière, Lyon [Geology and gem deposits in Sri Lanka]. E.G. [Gemmological analyses on site of the Crown Zoysa, Revue de Gemmologie A.F.G., No. 198, 2016, of Notre-Dame de Fourvière, Lyon]. L. Forest, G. 19–21 (in French with English abstract). Lomonosov in Russia: A new promising diamond * Article freely available online, as of press time source. R. Shor, GemGuide, 36(1), 2017, 2–5.

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462 The Journal of Gemmology, 35(5), 2017 Silver, Freiberg, Erzgebirge, Saxony, Germany Specimen courtesy of Collector’s Edge Minerals, Inc.

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Padparadscha Sapphires from Sri Lanka • 4.04 ct, 10.08 x 7.55 x 5.72 mm • 2.66 ct, 7.77 x 7.5 x 5.3 mm Blooms from Pala International Grounds • Photo: Mia Dixon